Category Archives: Informative

When it comes to hedges, there are certain things we want from the plants we use. When choosing which plant to buy, it is best to go through a check-list of what you need, and what the different choices offer. Let’s look at the most important features and see how some common hedging plants stand up to some scrutiny. If you use check off these features against the different plants you are considering, you can eliminate the guess-work and be able to make the right choice for what is often an investment that will last for 30 years or more.

Should be evergreen

It is true that the nearest thing to an ‘instant hedge’ will be a deciduous plant, perhaps one of the fast-growing willows. These can grow 6 feet or more in a season, which is much faster than any evergreen. But the downside is pretty much a deal-breaker. For several months of the year you can see straight through your hedge, destroying any ideas of privacy. Now sometimes this doesn’t matter. For example, in a larger garden it is common to use internal dividing hedges, and in winter these can be bare without it becoming an issue. In fact, letting the low winter sun through can be a big plus factor. Trees like beech make beautiful deciduous hedges, and beech has the advantage of often holding its brown leaves for most of the winter anyway.

But when privacy is an issue – and for most gardeners it is the main reason for planting hedges – the evergreen plants are really the only way to go.

Should stay green all year round

A problem with some evergreens is discoloration during winter. The foliage of some plants turns brown – usually called ‘bronzy’ – or scorches with the combination of sun and low temperatures. Since in winter your hedges are often the most prominent thing in your garden, how much nicer is it if they are rich green through the coldest months? It might take some research to confirm that the plant you are looking at does this – nobody advertises defects – but two good choices that are always green are Thuja Green Giant and Emerald Green Arborvitae.

Should grow fast

Every plant takes time to grow to where we want it, but some of course take longer than others. Only you know how quickly you want a mature hedge, or how long you are prepared to wait. Some trees that produce very long-lived and beautiful hedges take a long time to get there – yew trees for example. Others do it very fast – Thuja Green Giant will add at least 3 feet a year from the second year of planting until about the fifth, after which it will slow down to a foot or two. But that is ten feet in 3 years, and often enough to give you what you need. That tree has been proven in research to be the fastest-growing evergreen, but climate plays a part too, and in colder areas you cannot expect suitable plants to grow as well. Emerald Green Arborvitae is great in cold zones – it is hardy to at least zone 3 – but it will only grow a foot or so in a year.

Should be hardy

Make sure the plant you choose is well-matched for your growing zone. If you don’t already know it, it is easy to enter your postcode and find out. Often it is possible to ‘push’ your hardiness zone with many plants, and grow one zone colder than it says, but don’t try this for hedges, because they are too important to risk them being wiped out in a harsh winter. So always select plants that are thoroughly hardy in your zone. This applies at both ends – something often overlooked when you live in warmer places.

For example, if you live in a moderate zone – usually considered to be zones 5 to 7 – then Thuja Green Giant is the perfect choice. In colder zones use Emerald Green Arborvitae, as it is hardy throughout zone 3. It also makes a good choice for a smaller hedge in warmer zones up to 7. In warmer areas Thuja Green Giant will do well in zones 8 and 9 if your local climate is not too dry. If you have long, hot, very dry summers (often called a ‘Mediterranean climate’) then a plant that thrives around the Mediterranean is the best choice – Italian Cypress, either in its natural deep green or in one of the bluer forms, is very drought resistant indeed, and grows very well in hot and dry locations, as well as making great specimens in areas as cool as zone 7.

Should tolerate both sun and shade

It is a bit unusual to be putting in a long hedge that is always in full sun for its entire length. Except for yew trees, which tolerate shade well, but grow slowly, most evergreens do best in sun. But if your hedge will pass through both sun and shade you want to choose a plant with reasonable shade tolerance. Most Arborvitae need plenty of sun, or they grow very slowly into thin, open plants. But Thuja Green Giant will grow almost as well in 50% shade as it does in full sun, making it a great choice for this difficult but common situation.

Should be drought resistant

We accept that for the first few years we are going to give our new hedges some care, in the form of regular watering in summer. Once they become established, though, we would like to be able to leave them to take care of themselves. If we only have to trim once or twice a year, that would be ideal, as most people have limited time for their gardens. Summers can vary a lot, and even in places which normally have regular summer rain, drought year happen. So look for good drought resistance in established plants, unless you have unlimited water available, and a full irrigation system. Thuja Green Giant is more drought resistant than most evergreens, although Italian Cypress certainly beats it, surviving months of dryness without damage.

Ready to choose?

Now you have a better idea of what to look for, making that final choice of plant variety for your new hedge is a lot easier, and you are much more likely to have a top-rate outcome, and soon see the hedge of your dreams, right in your own garden.

As the full force of summer arrives, and high temperatures are already being recorded across the country, it is time to think about protecting our plants from drought. With unlimited water and time, or automatic irrigation, it is of course no problem, but many people are making the decision to reduce their garden water usage, either by choice, because of rising water costs, or because more and more cities are placing restrictions on watering your garden, either permanently, or seasonally, which usually means exactly when your plants need it most.

While Thuja Green Giant is not a true ‘xeric’ plant, it does have considerable ability to resist seasonal drought, at least, when it is well established. So the first order of business in making your screens, hedges and specimens of this fabulous evergreen drought-proof is to establish it well. After that we need to conserve the moisture already in the soil, and when we do need to water, make sure we use as little as possible, and get it where it can do the best job of keeping your plants alive. Let’s look at those things in turn.

Establishing Thuja Green Giant for Drought Resistance

Moisture levels in soil increase as we go down, until very often we reach a level where ground water is permanent, and there is abundant water available. In practice that is usually too far down for tree roots to reach, but every few inches deeper means more water, so the first step in making your plants drought-proof is to make their roots spread as deeply as possible. As well, a larger volume of soil from the surface down will make it easier for your plants to find enough water.

Deep Soil Preparation

This is the key, and it means a little extra work when preparing your planting site. Although you may be spacing your plants 5, 6, 7, or 8 feet apart, digging small individual holes is not ideal. A much better approach is to create a broad strip of prepared soil the whole length of your planting, as this exposes a much greater soil volume for your plants to penetrate. Run a string along the route of your hedge or screen, making sure it is 4 to 6 feet inside your property line, and then mark it a minimum of 3 feet wide. If you can, wider is even better. That whole strip should be deeply dug, either by hand to the full depth of a full-sized spade, or by rototiller.

If you use a rototiller, one quick run along the area is not enough (sorry!). It might look great, but that beauty is only ‘skin deep’, and almost certainly you have only tilled a few inches down – stick a spade in if you don’t believe it. Ideally you should pass along the area two or three times, as slowly as possible, and holding the machine back so that it digs deep. By the time you are finished the digging tines should be invisible, and deep in the ground.

Add Organic Material

Besides its nutrient properties, organic material (garden compost, animal manure, rotted leaves, etc.) is a great water-retainer. By adding it to your soil you increase the water-holding capacity greatly, without reducing air penetration, so the roots remain healthy. Remarkably, this is true of both sandy soils, where it seems obvious, and heavy clay soils, which we (wrongly) figure have lots of water in them. [Because they are so fine, clay soils don’t release a lot of the water in them – it remains trapped and unavailable to plants.] So spread a layer several inches thick across the planting area and till it in – it will really make a difference in every soil.

Water to Encourage Deep Rooting

Once planted, your new Thuja Green Giant plants need to spread their roots wide and deep, so they can access as much water as possible in future dry periods. This means watering the right way, to encourage that. At first, for perhaps the first month, the water needs of your new plants must be supplied from the roots in the root ball that was inside the pot – that is all it has. This means watering close to the stem of the plant is essential, and if the weather is hot this might be needed every 3 days. In ordinary spring and fall weather, do it weekly.

As well, we want to encourage those roots to move out from that small volume, and to spread into the surrounding soil you have carefully prepared. They won’t do that if the soil is dry, so you also need to water over a larger area than just where the root ball is. After that first month, avoid watering close to the stem, and focus on deep, weekly watering of a wide band of soil around each plant, or ideally, along the whole row. Get those roots moving out!

Maintaining Established Thuja Green Giant during Drought

Once your plants have spent that first season getting established, we now want to keep those roots spreading, but as we said earlier, getting water to them can be tricky, so we want to encourage independence and conserve what is already there.

Conserve Moisture

The classic way to conserve moisture in soil is with mulch. Any material, from plastic to paper, bark or gravel, that we lay over the soil will conserve moisture by reducing its loss from the surface. Yes, if you don’t mind the look, spreading out the local paper, or the Sunday New York Times, over the ground, and holding it down with a few rocks or some scattered earth, is a great short-term mulch. Even better is a 2-inch layer of that rich organic material you used to prepare the ground. That really is a better choice than bark, shredded wood, or stones, although cost is a significant consideration too. Rich material will rot down in two or three years and need replacing, but it will also fertilize your plants and maintain the water-holding capacity of your soil, so it is a much better choice.

If you don’t want to, or can’t mulch, then keeping the soil cultivated actually conserve moisture. The surface dries, but the broken up soil doesn’t draw much water from deeper down, and acts as a ‘soil mulch’ – it’s a useful tip, as well as keeping your planting looking great and weed-free.

Keep All the Water You Apply

If you have done things right, watering should be a last resort, and only needed during extended dry periods. Even if your plants look sad, if they are well-established, they will stay alive and come back when you can water again. If water restrictions are not in place, the simplest and most obvious way to water your plants is to grab the hose and start squirting, right? In fact, that is the worst way to do it. Large amounts of water evaporate before it reaches the ground – and the finer the spray the more you lose. So you pay for water your plants never even see. As well, you damage the soil surface, compacting the ground and drawing water more rapidly to the surface where it evaporates. (Mulch will of course prevent that compaction, another plus for doing it.)

Much better is to let water trickle gently into the soil from a slow-running hose. It will spread sideways too as the soil becomes wet, although not so much on very sandy soil. Even better is to weave a soaker hose (shown above) in and out through your hedge, as it will gently spread water over a large area, and this method uses a lot less water that standing there with a hosepipe!

The Botany of Thuja Green Giant – Part Two

Most gardening blogs are about how to grow plants, and here on Thuja Green Giant we certainly write lots of helpful and accurate information about that. But there is more to plants than growing them, and as we explained in the first part of this blog, garden plants are also a great door into the world of botanical science. In this and the previous blog we are looking at Thuja Green Giant with a botanist’s eye, rather than a gardener’s. In the first part we looked at the place of Thuja Green Giant is the bigger scheme of things – its position as a conifer, and what makes them special, and where in conifers it belongs.

In this part we will focus on the place of Thuja Green Giant in its genus, and on a botanical description of the plant itself, and its origins. Hopefully this will be of interest to horticulture students, professionals in landscaping and horticulture, and to interested gardeners who want to know more about the plants they grow.

A genus is the smallest grouping botanists use in their classification of plants. We can think of this as like a human family, with each member of the family being an individual species closely related to the other members. Don’t confuse this with the botanical concept of Family, which is a larger grouping of related genera – perhaps closer to our idea of nationality. Thuja is in the family Cupressaceae, which also contains cypress trees, juniper trees and redwood trees. In all there are close to 30 genera in that family, totally about 140 individual species.

Thuja itself is a small genus of currently five species, with two found in North America and three in Asia. These plants are commonly referred to as Thujas, Arborvitae, or Cedars. The last name is confusing, as there is a whole group of other conifers that are Cedars, in the genus Cedrus, and they are very different. Arborvitae is a much better common name, but its use is patchy. All the Arborvitae have stringy bark, which is reddish-brown in color, and grow into tall forest trees with a single trunk, although the Eastern Arborvitae (Thuja occidentalis) is often multi-stem, and it is also not especially tall. The branches end in sprays of small ‘branchlets’ which spread out in a flattened fan shape.

Thuja (and some other conifers) has two types of leaves. Young seedling plants have short, triangular, pointed leaves growing all along the stems. These juvenile leaves continue for at least a year, and we think they are like this to make the seedlings less attractive to grazing animals, so increasing their chances of survival during that difficult period.

As the plants grow taller, they develop adult leaves. These are decurrent – that is, their bases grow down along, and are attached to, the stems. The adult leaves are of two kinds. On larger branchlets they have a sharp tip 2mm (about one-eight of an inch) long, and that is turned up away from the stem. On the flattened branchlets the leaves the leaves are pressed tightly onto the younger stems, like scales, which is why it looks green and ‘leaf-like’. There are four vertical rows of leaves that cover the younger stems completely. So there are two rows of leaves facing outwards, called ‘facial’ leaves, and two rows facing sideways, called ‘lateral’ leaves. The facial leaves are flat, but the lateral ones have a ridge along them, like the keel of a boat.

Botanists use detailed differences between the relative lengths and forms of the leaves to distinguish one species of Thuja from another, while experienced gardeners can often tell by the overall ‘look’ of the tree which species it probably is. Only a botanist can give a definitive answer!

Because Thuja are conifers, they produce cones, although these are not much like the pinecones most of us know. There are separate male and female cones. The male cones are small, at the ends of branches, and consist of just a few thick scales, making a tiny ‘cone’. Pollen is produced in spring from between these scales, and they are carried by the wind to female cones on other trees. The female cones are lower down on the sides of the branchlets, and they are larger, 9 – 14 mm (about ½ an inch). The female cone has 8 to 12 scales, arranged in pairs rotating around a central axis. When young they are greenish and the scales are closed, making a pea-like object. As they mature – which they do in a single year – they become brown and the open, releasing one to three seeds from the inner surface of each scale. Remember? These Gymnosperms produce ‘naked’ seeds, right on the surface of the seed-producing organ, not inside an ovary, as flowering plants do. This means that we see the seeds right there, sitting on the scale. The seeds have a wing of thin, papery tissue on either side, to help them blown away in the wind and spread to new places.

There are two species of Thuja growing wild in North America. In the east we find Thuja occidentalis, a tree of wet areas, and very winter hardy. It grows up into Canada, as well as all through the eastern states, especially around the Great Lakes and in the Appalachians. Trees are typically about 50 feet tall when mature, but there are exceptional trees that reach 125 feet in height. It can be a long-lived tree, where deer and fire do not reach it, and specimens over 1,500 years old have been found growing on rocky cliffs in Southern Ontario. This makes them the oldest trees in eastern north America. This tree is called northern white cedar, or eastern arborvitae. The name ‘arborvitae’ means ‘tree of life’, because a tea made from the foliage is rich in Vitamin C, and Native Americans taught early European explorers and settlers to use it in winter. It prevents scurvy.

 In the west we find Thuja plicata, a larger forest tree, usually called western red cedar or western arborvitae. This tree is much taller than its eastern brother, and it often grows over 200 feet tall, in time, with a massive trunk that can be 10 to 13 feet in diameter just above the base. This tree also grows old, well over 1,000 years, with the oldest specimen known being 1,450 years old. This tree is one of the parents of Thuja Green Giant.

The second parent is one of the three Asian species, Thuja standishii. This tree is called Japanese Thuja, and it grows in southern Japan, on the islands of Honshū and Shikoku. It is a forest tree that can grow over 100 feet tall. We have described in other blogs the fascinating story of the origin of Thuja Green Giant as a hybrid between western arborvitae and the Japanese thuja. The other two Asian species are Thuja koraiensis, a species found in Korea and part of northeastern China. It is a small, shrubby tree growing no more than 30 feet tall. The final species in this genus is Thuja sutchuenensis, the Sichuan cedar, from western China. It is a small tree, that may reach 60 feet, although no trees alive today are that tall. This tree was thought to have become extinct, because it was harvested for its fragrant wood. Then a small group was discovered in 1999, and the area is now protected.

These are the trees of the genus Thuja, and we hope this helps you understand more that hedge or screen you have of Thuja Green Giant.

The Botany of Thuja Green Giant – Part One

One of the great things about gardening is its natural interface with the science of botany. There, in your garden, is a whole display of the breadth of the Plant Kingdom. (Or at least the more advanced parts of it, since algae don’t figure much in most gardens.) Mostly on this blog we think and write about the practical side of gardening, the “How Too” stuff, but looking more closely at your plants is an easy way to open the door into the science of nature and understand more about the plants on which we depend. Since Thuja Green Giant is found in many, many gardens, why not start with it? After all, the entrance to science has many doors. With that in mind, for gardeners who want to know more, and for students of horticulture and botany, young and old, here is a botanist’s look at this popular evergreen.

Evergreen or Conifer?

Let’s start right there. In the garden we usually refer to all plants that stay green all year as ‘evergreens. But it doesn’t take much observation to notice that really there are two distinct types of plants in this group. First there are the plants that have similar leaves to deciduous trees and bushes – flat, green leaves that are broad and thin. These are often called ‘broadleaf evergreens’ to distinguish them from the other kind, those with needles, like pine trees, or with green stems that don’t really have what look like leaves at all, but that are green. The first group are just plants that live in warmer areas, and they see no particular need to drop their leaves for winter, so they don’t. Their leaves may live two or three years, and often drop in spring, when new growth comes, rather than in fall. Often they are closely related to plants that do lose their leaves for the winter.

Thuja Green Giant belongs in that other group, which is more correctly called conifers. These plants are very different. To begin with, they don’t have flowers, which botanists define as a structure with enclosed seeds. Instead, these trees are Gymnosperms, and they have their seeds sitting open on a leaf like structure. It is this fundamental difference that put them into their own group.

The History of Conifers

The first Gymnosperms appeared around 350 million years ago, during the Carboniferous age, when the great coal and oil deposits we use today for energy were being formed. Their exact origin is not clear, but they may be evolved from earlier plants that were fern-like, but that produced seeds on their leaves. If you have seen Cycads, those strange plants that look half-fern and half palm tree, you have seen the earliest forms of these plants. Despite their appearance, these ancient plants have large cones that look very like those on pine trees!

Shortly afterwards two other groups formed. Of one, all we have left is the beautiful maidenhair tree, Gingko biloba. Although we might think this was a flowering tree, the structure of the wood and of the ‘fruit’ shows it to be part of the Gymnosperms.

The Different Conifer Groups

The other group formed by that division is today the most widespread and common – the conifers. There are about 1,000 species still with us, and many more extinct ones, since the rise of flowering trees pushed these plants to areas like the far north, where they could compete successfully. Within the Conifers (called Pinidae), are three large groups, called ‘orders’. These are, firstly, the pines and their relatives, like firs, spruce and true cedars – all tree with needle-like leaves. Then the South American tree called Monkey Puzzle, Araucaria, and the Asian Buddhist Pine, Podocarpus, are grouped together with several other conifers not normally seen in gardens. Third we come to the group containing many of our garden conifers, including redwood, bald cypress, hinoki and sawara cypress, and arborvitae. Yew is also included in this last group, which is called the Cupressales. Within it are three ‘families’, and it is in the one called Cupressaceae that we find Thuja Green Giant.

The ability to test the DNA of plants has led to many changes in our picture of their relationships. It is usually not the DNA of the plant itself that is studied, but the DNA of the chloroplasts – those green parts in the cells that carry out photosynthesis. These structures have their own DNA, and since they reproduce inside the cell by simple division, their DNA changes much more slowly than that of the plants they live in. So they are the perfect guide to long-term relationships between different plant groups. Carefully analysis has allowed us to create clusters of plant groups, and to see exactly how they are related. The resulting changes have bothered many gardeners and nursery growers, but they give us a much better picture of the plants around us.

The Genus Thuja

As a result of all this work and analysis, we now know that Thuja, the ‘genus’ of Thuja Green Giant, is most closely related to a whole cluster of genera of popular garden conifers. In that cluster are Chamaecyparis, which has the important and very varied Japanese cypress trees. As well, in that same group, we find Cupressus, the true cypress trees, from both Europe and North America, as well as the Junipers (Juniperus), which are found all across the Northern half of the world. This family is called Cupressaceae, the cypress family.

We can think of a genus as being like a human family which contains, instead of individuals, groups of individuals very similar to each other, called species. Some genera (the plural of genus) are large, while others are small, sometimes containing just one species. The closest relative of all to Thuja is a single Japanese tree called Thujopsis dolobrata, the asunaro tree, which is very similar in appearance to the Hinoki Cypress. Remember that these divisions are in the end arbitrary, and it depends on how big a difference botanists think is necessary to create a new genus, especially when it contains just one species, as Thujopsis does. For the moment at least botanists are keeping it separate, but that could change in the future. The organization of plants into groups is a human activity, which plants are ignorant of. As gardeners we are best to remember that, so that we see the regular changes that occur as man-made, while nature itself remains just what it is.

In the next part of this blog we will look more closely at Thuja and explore its structure and relationships. Who would have thought that Thuja Green Giant could open so many doors into the science of botany!

Thuaj Green Gaint Screen

Thuja Green Giant for Screening and Shelter

A top priority for many people is privacy. No-one likes to be on their property and being viewed by passing cars, nearby homes, or from apartment buildings. The value of a home reflects this – if you lack privacy your home will be harder to re-sell. So adding shelter and privacy is often the first piece of gardening done, and sometimes the only major part – a garden with screening, a lawn area and perhaps a couple of trees is fine for many people.

Our minds tend to jump to hedges when looking for that privacy, but hedges can be a lot of work, especially tall ones, which can be needed if your privacy issue is being overlooked from nearby buildings. So instead of thinking ‘trimmed hedge’, why not think ‘screening trees’ instead? With no trimming needed, a well-planned screen will take care of itself for many years, and once established ask absolutely nothing of you – surely a great thing in these days of us always being busy.

Choosing the Right Plant

Suitable plants for this will be fast-growing – because who wants to wait a decade or more while your screen grows? – and evergreen. While deciduous trees can often be grown quickly into a screen, all through the winter months they are pretty transparent, so the privacy is limited to summer, which is often not enough. The plants also need to be self-supporting without trimming, and they must give cover all the way to the ground. To do that you need plants that are relatively narrow and upright, because plants with broad crowns will always become bare at the bottom, there simply isn’t enough light penetrating to keep the lower branches alive for too many years.

A plant that really satisfies those criteria is Thuja Green Giant. This arborvitae is a relative of the white cedar known to many people in the north-east. A hybrid plant, it combines an Asian and an American tree, and hybrid plants are well-known for vigor, rapid growth and resistance to pests and diseases – this one is no exception, and incredible tough and reliable. Thuja Green Giant is certainly fast growing. Independent trials have shown it to be the fastest of all the evergreen trees. They usually take a growing season to become established, adding a foot or two in height during that time. Then this tree really takes off. For the next several years it will add 3 or even 4 feet a year, so that your trees will easily be 10 to 15 feet tall within 5 years. After that the growth does slow down a little, but by then you have a substantial screen.

Planning the Planting

Often, when putting in a screen, trees are planted too close together. The idea is that this will give a solid screen sooner, but it’s a mistake. Plant too close and each tree will fight with its neighbors, growing tall, yes, but not thickening up. A spindly, narrow planting is the result, which is easily damaged by wind and snow, and which remains open lower down. In fact, the bottom branches will often die in a few years, completely defeating the purpose of the planting.

The goal should instead be to develop sturdy, bushy plants, which Thuja Green Giant will do naturally, and well, if given a little room. For a screen that won’t be trimmed, it’s especially important to give each plant enough room, because they need to stay bushy, without shooting out all over the place, which crowding will cause.

Within seven years even a small plant of Thuja Green Giant will have grown to be 10 feet tall and 5 feet wide, so that 5 feet is a good planting distance apart for a screen. The young plants won’t crowd each other, and they will each develop into sturdy individuals, able to stand up alone, with dense growth to the ground, and no need to trim. You could easily extend that spacing to 8 feet, and still have solid coverage within ten years. Remember too that you don’t need a solid wall to reduce wind-flow and give privacy everywhere except at 90 degrees to the line of your screening. Not only do you reduce the cost of your investment in this screen, you get a result that requires no maintenance. Even when the plants do start to grow together, they are sturdy enough to do that without weakening and being easy for storms to break.

Usually a single row is planted, but if you have more room a double row will give you better screening sooner, and a more solid barrier to noise and wind. Space the two rows 5 feet apart, and stagger the plants, so that each one sits in the gap of the other row. They can be 8 feet apart in the rows, or even more, up to 12 feet, and you will soon have a fabulous, dense screen that needs no work at all.

Initial Care Makes a Big Difference

Thuja Green Giant will certainly grow fast, and well. But some care in preparing the planting area, and in looking after your plants during the first year or two, will still make a big difference.

  • Soil Preparation – even the best soils benefit from adding some good-quality organic material before planting. Garden compost or rotted manures are best, but almost anything, from rotted leaves to peat moss, is beneficial. Dig good-sized planting holes, three times the width of the pots your trees are in and mix 2 or 3 buckets of organic material into the soil.
  • Fertilizer – because it takes time for the root system to spread outwards, and for your trees to enjoy that rich soil you have prepared, applying liquid evergreen fertilizer during the first season, and even in the second one. Liquid fertilizers are much more effective on young plants than granular ones, but they are more work, so by the third season you can switch to a slow-release granular formulation that only needs one quick application a year, in spring.
  • Watering – after planting your trees are still almost completely reliant on the soil from the pot that is around their roots. So for the first few months you should water close into the stem at least once a week, or more frequently during the hottest and driest part of the summer. Keep the surrounding soil damp too, otherwise your trees will have no reason to spread outwards. By the next season the roots will have spread out considerably into the surrounding soil, and you should only need to water during dry periods.

Watering Thuja Green Giant – Everything You Need to Know

How and when to water plants is always an issue, and one of the most common basic questions about Thuja Green Giant, and almost every other garden plant as well. It is said that in Japan an apprentice gardener had to work for 7 years before being allowed to water plants, so if you find it a tough issue, no wonder!

Thuja Green Giant is certainly a sturdy and reliable evergreen, but it too needs the right amounts of water, at the right times, so let’s take a look at the issues around watering properly, to have the greatest success.

Watering Before Planting

Good planting is the key to success with almost all plants, and Thuja Green Giant is no exception. When it comes to watering, there are two key things to keep in mind, and to do. The first ‘rule’ is never to plant a dry tree. If the root ball inside the pot is dry, the roots exposed to the air when you take off the pot will quickly dry, and they can die. As well, a dry root-ball can repel water, so it is easy for it to still be dry after you have planted – something that should definitely be avoided.

The best way to make sure these problems don’t happen is to water your plants, in their pots, thoroughly the evening before you are planning to plant them. Just give each pot a thorough soaking, allowing plenty of water to flow through the drainage holes in the bottom of the pot. If the plant is very dry, even that may not be enough, as a dry root-ball will shrink away from the pot, allowing water to flow through without wetting the soil much at all. If you think your plants are very dry, then take a large bucket, fill it ¾ with water, and place the plant and pot into the bucket. It may float for a while, but don’t worry, soon it will sink and become thoroughly wet. After 15 minutes to half an hour, lift it out, allowing the water to flow back into the bucket, and then place it on the ground to finish draining. Repeat as necessary until all your plants are properly wetted. Good job!

Watering During Planting

Now you have good moist root-balls, you are ready to plant. Here too, some people make the mistake of waiting to water until they are all finished. Then a quick splash with a hose is all that happens. No, there is a better way. You want to have the water deep in the soil, around the root-ball, to attract those roots outwards. So when you have put back about 2/3 thirds of the soil, firm it down around the roots, and then fill the hole to the top with water. Wait for that to drain away, and then put back the rest of the soil. You really don’t need to water again, unless the soil you are planting into is very dry. So no muddy puddles, just a neat finish to your planting, and plenty of water where it is needed.

Watering After Planting

Follow-up watering is vital for the successful establishment of your new Thuja Green Giant, and there are several factors to consider.

  • Time of year – if you are planting in spring, the warm weather and rapid growth of your plants means regular watering is needed. Once a week should do it. If you plant in summer, make that twice a week. If you plant in fall or winter, you may not need to water at all, although if you don’t see much rain, soaking every couple of weeks is worthwhile.
  • Type of soil – if you have sandy soil it will not hold much water, and it will dry fast (you probably already have experienced this!). You should increase the frequency of watering new plants accordingly. For example, newly planted trees in sandy soil in summer may need water every second day for the first couple of weeks, and then twice weekly for the first month. At the other end, don’t be fooled by clay soil. Although it looks sticky and wet, it becomes effectively dry to plants quicker than a loam soil does. Clay will bake hard and crack, which you don’t want, so keep to a good watering schedule with it.
  • Weather conditions – this one is just common sense. If you have unusually hot weather, you need to water more frequently.

So here is what to do: Water once a week for the first two months – allowing extra or less based on the points just raised. Then reduce that to every two weeks for the rest of the first growing season. In the second season, water whenever the soil looks dry for the top few inches. Don’t be tricked by thunderstorms and sudden downpours of rain, as these often only wet the top inch, and most of the water simply runs away into the drains.

How to Water

Now you know when to do it, here is how. Water should always be applied slowly, so although standing with a hosepipe spraying water can feel like a ‘good deed’, it is not very effective. Much better is to place a trickling hose a few inches from the base of your plants, and let it run for a while. The water will spread outwards, but more importantly, downwards, and everything will be well-soaked. Not only is this better for your plants, but you use less water too, as hand-sprays lose a surprising amount of water to evaporation, especially on a hot, dry day. When it comes to watering, slow and steady always wins out.

If you have a hedge, this method can take some time, so invest in a length of leaky pipe. This low-cost piping sheds water all along its length, and it can be coiled around and along a row of plants and left in place. Simply connect it to a hosepipe and turn it on for as long as it takes for the whole area to look wet. Once you have an idea how long it takes for your particular situation, you can install a simple timer on the tap, and it will do the job once a week without you having to do anything at all – what could be simpler?

About this time of year, in spring, a common distress call is about hedges that haven’t gone through the winter well. This is especially common if they were freshly planted in the fall before, and perhaps winter was severe, or very dry, or just not mild and pleasant. You step outside and see that your new Thuja Green Giant hedge is looking sad. Maybe there are some dead or brown twigs, the foliage looks yellow, maybe a few plants have been pushed over by heavy snow falls, and despite this being a tough and reliable plant, that is not what you are seeing! But don’t worry – this really is a tough plant, and with a bit of TLC you can soon have them back on their feet and growing strongly.

Get Your Thuja Green Giant Plants Growing Strongly

  • Firm them down and straighten them up – frost and snow can shift them around, and loosen the roots
  • Feed your trees and your soil – if you are planting in poor soil, adding soil microbes will bring it to life
  • Water – deep watering will get everything going – repeat each week for the first season
  • Put down a rich mulch – this will conserve moisture and feed both the soil and the plants
  • Tidy and trim – remove any dead or broken twigs, and trim back the tip to encourage bushy growth

Firm Down Around the Roots

In winter, when the ground freezes, the water in it expands. This lifts and loosens the soil. Sometimes this can be a good thing – in areas you plan to plant vegetables, for example – but for newly-planted bushes it loosens the root ball and makes it hard for them to send out new roots. New plants need to be in close contact with the surrounding soil, so that new roots can easily spread out from the root ball, exploring for food and water, and anchoring your trees.

If your plants seem wobbly and loose, or are crooked and not straight up, then take hold of the stem halfway down, straighten them, and use your foot to press the soil down around the root ball. They should be nice and firm in the ground, and they should be pointing straight up. If you now have footprints, take a cultivator or rake and level out the ground. Now they can get going, and you will have a good straight hedge too.

Feed Your Trees and Your Soil

If you have good soil, and an established garden, and you mulch regularly, then there is nothing wrong with using simple fertilizers that boost the levels of nutrients for your trees. Evergreens like Thuja Green Giant need plenty of nitrogen, so choose something blended for evergreens, which should have a big number at the beginning of the three-part formula on the package.

If you are starting a new garden, on a development site, or an area that has had a lot of construction activity, the chances are that the soil will be depleted. Not just of nutrients, but also of the necessary micro-organisms that create the complex soil cycles. These both break down nutrients and make them more available for your plants. There are several products available, but one of the best is Bio-Tone organic fertilizers. These blend natural, organic sources of nutrients, including those all-important micro-nutrients, with a range of specialized bacterial spores, which germinate in the soil and establish colonies. These release the nutrients, and also begin the natural development of the soil ecosystem.


How often have you read the importance of watering? Well it’s true – plants can’t grow without water, especially when they are newly planted. I likely reason your Thuja Green Giant don’t look good in spring is if they were not deeply watered in late fall – something you should always do. So make up for it with a good, deep soak this spring. Rather than standing with a spray on your hose, set it up to run slowly beside the base of each plant, so that the water penetrates deeply.

Even better is to install a simple irrigation system. The easiest, yet one that is very effective, is a leaky pipe system. These are black pipes made of a porous material, that drip water all along their length. They are perfect along a hedge, undulating like a snake between the trunks, and covering further out too. You can even put a timer on the tap and set it to come on for a few hours once a week – maybe twice during hot, dry weather if your hedge is new.

Put Down Some Rich Mulch

Hopefully you added some rich organic material when you were planting, but even if you did – and especially if you didn’t – putting down a layer as a mulch is a great idea. Materials like garden compost, rotted cow, horse or sheep manures, mushroom compost, or even rotted leaves, are much, much better for your soil than using bark chips, shredded bark or pebbles. Those material might reduce water loss, but they do nothing for your soil. Rich materials build richer soil over time, and that is the secret to having your plants grow well.

A mulch layer should be 2 or 3 inches thick and cover well outside the area around the stem. Keep it away from the stems, and off the foliage, as it can rot the leaves and damage the bark. This layer will also reduce weeds, as the last thing you want is for your new hedge to have to compete with weeds for water and nutrients. Mulch can go down in late fall or early spring, and it should be renewed every few years, as it will decompose into the soil over time – which is a good thing.

Tidy and Trim the Plants

Once you have taken care of everything else, finish up by going over each plant with your pruners. Snip out any dead or damaged branches, and ones where the leaves have turned dry and brown right to the ends. This will not only make them look a whole lot better, but it will leave some room for new growth, and often stimulate it too. Thuja Green Giant will not re-sprout from branches with no leaves on them, so don’t leave any stumps. Then snip off the ends of the growing branches and straighten up the top by cutting back to all the same height. Regular trimming during the growing phase of a hedge is needed to build a strong internal structure, so don’t just let it grow to your desired height and then start trimming – that‘s a common mistake.

Now you have done all these things – which won’t take so long – you can look forward to seeing some strong growth on your new hedge, and a quick recovery to the beauty and vigor that this plant is capable of delivering.

If you do a little research, you will usually find that Thuja Green Giant Arborvitae is listed as an evergreen that needs full sun. Yet look around, and you will see good specimens and hedges of this plant growing pretty well in shade – so what’s going on?

To understand this a little better, we need to look more closely at the different types of shade in gardens. Understanding this will help you grow not only Thuja Green Giant, but all your other plants too. Basically, there are three or even four distinct types of shade found in gardens, and each of them has a different effect on plants growing in them. Once you understand the differences you will see why it is that you see the same plant doing well in shade in one place, and badly in another, including plants of Thuja Green Giant.

Types of Shade – One: Open Shade

The first type of shade we find is what is often called open shade. What is ‘open’ about it? Simple – just look up. Can you see the sky, free of tree branches or any other obstructions? If you can, then you are looking at open shade. Even though the direct rays of the sun don’t come through, the atmosphere scatters and spread the light, and all the wavelengths of sunlight are present, in a very similar balance to direct light. This is important, and it explains why many plants will grow well in these locations. We find this kind of shade on the north side of buildings (or south side, if you are reading this in Australia, New Zealand, South Africa or most of South America) and in the shadow zone cast be trees, most noticeably between fall and spring.

Sunlight contains all the wavelengths and colors of visible light – all the colors of the rainbow. Plants use mostly red, and some blue light, but not green light. This is why they look green – the green part of the light is reflected back to our eyes, and the other colors are absorbed for photosynthesis and growth. Open shade gives plants all the necessary colors, just less of them, so growth is possible, even if it is reduced. Indeed, many plants grow very well in open shade – hydrangeas for example. Especially in hot states, and in the south, some plants prefer to be in open shade, since the very strong sunlight can burn the leaves and inhibit growth.

So if you want to grow Thuja Green Giant in a place in open shade, it may grow well. Not as fast as in full sun, and it may not be quite as dense, but this reliable plant will survive and grow, especially if it gets a few hours of direct sunlight, as we will discuss a bit further down.

Types of Shade – Two: Overhead Shade, Deciduous Trees

If you look up in this kind of shade, you will see that it comes from tree branches overhead. These may be solid and dense, or they may be more open and showing some blue sky. They may be close overhead, or high up above you. The denser and closer they are, the less light there will be. This kind of shade has another disadvantage. Most of the light that reaches the ground has passed through the leaves, and the valuable red and blue colors have been extracted by the chlorophyll. This creates that lovely cool look in shady spots – at least to us – but for plants growing in these areas the light has less value, because a lot of the ‘photon goodness’ has been taken out before it reaches them. This is why plants that will grow happily in open shade will grow less well in overhead shade.

Now, the shade from deciduous trees has some advantages, because in spring most trees are slow to leaf out, allowing much more direct sunlight through. In fall too, after the leaves have gone, light comes through, and in warmer, southern areas this is especially helpful in winter, where temperatures may be warm enough for plants to still be growing slowly. So a Thuja Green Giant, planted in the overhead shade from deciduous trees, especially in a warmer zone, may still do OK. It will certainly be a bit thin and more open, but with some trimming it should be possible to keep a reasonable look to it.

Types of Shade Three – Overhead Shade, Evergreen Trees

Now we come to the really difficult shade, the sort of thing you find underneath a big old spruce or fir tree, or a laurel bush. Not only are many evergreens very dense, allowing very little light through, but the shade is unrelenting, just as dense in fall, winter and spring as it is in summer. Gardeners know from experience just how few plants will grow in these conditions, especially if the branches are low and close to the ground. Here, Thuja Green Giant is simply not going to make it, so use something more shade tolerant, like Yew or Plum-yew (Cephalotaxus).

Types of Shade Four – Seasonal Shade

Most of us know that the sun is in the sky for longer in summer than in winter – pretty basic stuff. As well, the sun is higher in the sky in summer, especially between the two equinoxes, March 21 and September 21. Each day up until June 21 the sun is a little higher, and then it goes lower again, until everything turns around on December 21 and starts again. So if you look at your garden in winter you will see a lot of shade, from buildings and the long shadows of trees, especially evergreen ones. But as the shadows shorten, areas that were in shade are now in full sun, and this coincides with the growing season too. If you plant Thuja Green Giant in a spot that is only shady in winter, it will grow almost as well as in a spot that is sunny all year, because most of the growth happens between spring and fall, even though the plant is evergreen. If you want to know if you can make a hedge with this great plant, or plant a specimen or two, it is best to look at the available light during the summer period, as any shade in winter has very little effect.

Ah, I See. . .

It’s obvious that shade is a complex subject, and simply rules like ‘grow in sun’ have to be thought through in each garden, and the areas more closely identified. Then you will be able to plant more effectively and get ‘the right plant in the right place’. Hopefully that will mean that you can grow Thuja Green Giant in more places than you thought possible.

Planning and Laying Out Hedges

Hedges are a critical part of a garden, providing privacy and shelter. Gardens inside hedges are warmer that exposed ones, and they allow you to grow a wider range of plants, especially ones at the limits of their hardiness. With a more private garden you will find yourself using it more, and feeling more relaxed, knowing you are not the object of casual – or deliberate – gazes. Planning those hedges is therefore an important job, and one often done at the start of creating a garden. Often, though, we see hedges that have not been planned well, and that don’t serve the intended purpose as well as they might, and can lead to problems with neighbors, your city, or just within your family. With all that in mind, let’s take a look at the planning stage of hedge planting.

Follow These Tips for the Perfect Hedge

  • Decide where they are needed – spend some time figuring out exactly where you need the screening and shelter. Wind direction can be important.
  • Space back from property lines – make sure all your hedge is yours. Anything hanging over a neighbor’s land can legally be cut off, and that could be most of your hedge.
  • Find the minimum effective height – a bit of simple math will show you exactly how high you need to go – it may be less than you think.
  • Create Internal Screens too – creating garden rooms with hedges turns a large, open property into a wonderful series of varied spaces

Where Do You Need That Hedge?

If we split the main functions of hedges into their parts, we can look at privacy, screening and shelter. These goals may conflict, or they may mesh with each other. Reconciling them with the best outcome is obviously a good idea!

Privacy is usually the more obvious need, and it may also be the easiest to satisfy. Stand in your garden and look around – do you look onto a highway or road? Are there windows overlooking you? If there are, is this a part of your garden where that matters? After all, in the front yard may want to be seen – remember that important ‘curb appeal’ – and most of us don’t use the front garden for private activities anyway. If you do plant a hedge, just to mark your boundary, the chances are that you won’t want it tall, and 2 or 3 feet will probably be best. You might also want to consider something informal, like a row if flowering shrubs, all of a similar size.

As well, if you only have a few points where your privacy is invaded, then maybe a cluster of upright evergreens will do the job, without a full hedge. The same is true of ugly views – maybe you don’t need a complete hedge to obscure it, and can be more casual, with clusters of evergreens strategically placed. Working with another person to see just where you need to be to give you the desired screening is a good way to go with this.

When it comes to shelter, and reducing wind, you need to first off all find out the direction of the prevailing winds where you live. Maybe you need shelter from cold winds in spring and winter, or maybe hot, dry ones in summer. Neighbors may know but try your local weather station for the best information on this. Then use a compass to figure out that direction. To be effective in filtering wind, a hedge needs to cut across the wind direction at right-angles, or close to it. This may or may not correspond to your property boundaries, so some creative design might be needed! There really is no hard-and-fast reason why a hedge has to run along a boundary.

Set Your Hedges Back from the Property Line

A common error when planting hedges is to plant along the property line. This can seem like a good idea, as it leaves you with the most space. The problem is that it puts everything over the line onto your neighbor’s land. That might not be a problem at first, but if that property chances hands, you have no idea of what could happen. In most places a neighbor can cut back everything overhanging their property, and if your hedge is throwing shade, for example, they may do just that, leaving you with a very poor hedge indeed.

Much better is to run the planting line at least 3 feet inside the property line, and 6 feet it better, especially when planting larger evergreens like Thuja Green Giant. That way it is all yours, or at least, enough of it is to avoid future damage.

Calculate the Height You Need

A simple bit of school math will show you exactly how tall a hedge you need. Say you want to hide the upper windows of a neighboring house. Estimate how high up the top of that window is, and how far away the house is. Then measure how far from the hedge you want to be screened. Use this formula to calculate the height of hedge needed.

Multiply the height of the window by the distance you are from the hedge. Divide the result by the distance away of the house. The resulting number is the height of hedge needed. For example, if you have a window that is 18 feet up, and the house is 100 feet away, then to screen up to 50 feet back from your hedge, you need a hedge that is 9 feet tall. (18×50 ÷ 100).

The taller a hedge is, the more effort and time is needed to trim it. Using this formula will minimize the height you need, and save a lot of trimming time, as well as minimizing any shade effect.

Use Hedges to Create Rooms in Your Garden

Many people think a hedge is just for the property line, and in a smaller garden that may be true. But on a larger property, internal hedges turn a big open space into a series of rooms, making a much more intimate and magical garden. They only need to be about 6 feet tall, and they allow you to separate the different activities – like a vegetable garden from a party/barbeque area, or to create a children’s play zone that is visible from the kitchen window. Or of course to make a retreat, completely private, to find peace in solitude.

Good Technique is the Path to the Perfect Hedge

With the first flush of spring growth well underway, it won’t be long before your hedges need trimming. Hedges are the basic architecture of many gardens, and the privacy and shelter they bring are essential for creating a personal garden space. Often they have a practical purpose, sheltering you from neighbors or traffic, but they also give form and structure, creating a stage for your plants to strut their stuff on.

Popular hedging plants like Thuja Green Giant have a natural density that makes it easy to grow them into solid green walls, but you also need to treat them right, and good hedges follow some simple rules for success.

Follow These Six Tips for the Perfect Hedge

  • Trim regularly – the more you trim, the denser it gets
  • Trim while your hedge is young – waiting till it reaches full-size is a mistake
  • Trim in the right seasons – too early, or too late, can cause problems
  • Slope the sides – an inward slope keeps the bottom green and healthy
  • Narrow the top – round or square, a narrow top sheds snow and ice
  • Feed and Water – like a lawn, you need to replace what you removed

Trim Regularly

Old-time gardeners don’t waste their words. They say, “The more you trim, the denser it gets”, and they are right. When you cut the tip off a growing stem, of any plant, it produces several new shoots a little below where you cut. Buds at the ends of stems produce a plant hormone that stops the dormant side buds lower down from growing. When you cut off that bud they are released from control, and spring into action. Think of how many tips you cut off with your trimmers going over a hedge. Multiply that by three or four, and you can see how many new stems you have. Many stems give us the crowded, dense growth that makes the perfect green wall. It really is that simple.

Trim from an Early Age

If there is one single mistake made when hedges are planted, this is the one. It seems logical that you would leave your hedging plants, like Thuja Green Giant, to grow to the size you want and then start trimming. But logic is not your friend on this one. A solid hedge that is resistant to wind and snow needs a strong internal structure of many short branches. Taking off just a little growth as your hedge is expanding will give you that sturdy structure. If you wait until it has grown taller, then all the density will be on an outside ‘skin’, and that makes your hedge vulnerable.

Start trimming as soon as you see new growth on your new hedge. Just take off an inch or so, regularly, and you will see how quickly it becomes solid. It will still grow up almost as quickly as if you left it alone, but this time you will have many branches, making a tough and sturdy hedge.

Trim in the Right Seasons

There is a rhythm to plant growth, and to the seasons. The longer days and warmer temperatures of spring trigger a big flush of growth, drawing on reserves stored in the previous year. The buds for that growth develop in late fall and early winter of the year before. So you need to let that first flush mature before trimming, as it is the new foliage that keeps your hedge dense and green. If you cut it all off, the older parts now have to make new buds to replace it, and the older leaves soon fall off, keeping the surface of your hedge always thin and weak.

To allow room for that new growth, without letting your hedge get bigger and bigger, you need to trim in fall, leaving all winter for the new buds to form. This also gives you perfect, tight hedges in winter, when they are especially prominent and visually important. When to make that last trim of the season depends on where you live. In colder area you should allow a full month before the normal beginning of cold temperatures and the chance of ice and snow – the odd morning frost is fine. That probably means mid-September is the latest time. In warmer areas you can trim later, often up to the end of November, depending on your climate.

Once the spring flush has started to darken in color, trim it, leaving a couple of inches of that fresh new growth. That trim will stimulate some more growth – a lot in a young hedge, less in an older one. How many times you cut between now and that vital fall trim, is up to you. At least once is usually necessary, and that will keep your hedge both neat and dense. For a super-hedge, make that two, one in early summer, and another in early fall, if you are in a warmer area.

Slope the Sides

This is another secret that is often ignored. The top growth of a plant is always more vigorous, and longer, than the lower growth. If you trim the same amount from all over your hedge, it will become fatter on the top, and narrower lower down. This will shade the lower parts and reduce their growth. In a short time the lower branches will die, and your hedge will be bare for several feet at the bottom – exactly where you want dense green growth.

So always slope the sides inwards just a little. You will be cutting more from the top than the bottom, but don’t worry about that. The less you cut from lower down, the better, as long as it is neat and flat. The best hedges have a flat side, like a sloping board, not a curve, and learn to keep that slope even all along the hedge – it is not difficult with a good quality, sharp hedge trimmer.

Keep the Top Narrow

Sloping the sides will naturally keep the top narrow, and that is something to encourage. A narrow top will shed snow and ice better, and the chance of your hedge collapsing is reduced greatly. With a narrow top you can keep it square and flat, if that suits your garden design, although rounding it for a less formal look is even better for shedding snow.

Feed and Water Regularly

Finally, trimming a hedge is like cutting the lawn. You remove material that is part of the strength of the tree, so hedges need more nutrients than untrimmed plants. Have a regular fertilizer program – organic or not, it’s your choice – and water during dry spells. It doesn’t take a lot of time, but that extra care, and the tips we have given, will make your hedge a stand-out feature of your garden.