Monthly Archives: June 2018

So you just planted that row of Thuja Green Giant? Congratulations, it’s the perfect choice for a a screen or hedge – but now you are wondering what to do next. So here is a check-list of things to do and watch for with your new planting, so that it grows as fast as possible – and that is fast – and soon looks like the image you had when you bought them.

Summer Care of Thuja Green Giant

  • Water regularly – soak deeply for several hours once or twice a week
  • Mulch – it controls weeds and conserves moisture
  • Feed it – liquid fertilizer is best for new plants
  • Trim lightly – don’t wait for it to reach full size before starting to trim
  • Relax – there isn’t much else to do with this easy-to-grow plant


The single biggest killer or growth-slower of new plants is lack of water. For the first season you need to keep watering close in to the stem of the plant, which is where the roots are. The biggest mistake with watering is to take the hose, with or without a spraying nozzle, and spend a few minutes spraying the ground. This water doesn’t penetrate very far at all, and the roots usually stay dry. Water needs to be applied slowly, so that it trickles down into the ground, and there are two ways to do that easily.

One easy way is to use an open hose, with the faucet turned down so it just trickles. Lay the hose a few inches from the stem and leave it for about half an hour. Check back and if the ground around the plant now looks thoroughly wet, move on to the next plant. If you do this once a week your plants should be really happy. At the height of summer, if there has been no rain and it is hot and windy, you may need to water twice a week – -check by scrapping back a bit of the soil to see if it is still damp or not.

The second method is a less work, so it’s a great choice if you have a longer hedge. Get a length of porous pipe and thread it back and forth around your plants, covering the ground with a sinuous line of pipe. You can use loops of coat-hanger wire bend over to anchor it in place and hold it down. It is best to do this before putting down mulch. This kind of pipe leaks all along its length, letting drops of water flow out onto the ground. How long it takes to soak the area depends on your soil, so you need to experiment, starting with an hour, and adjusting that time as needed. Adding a simple timer to the faucet makes it easy to do this automatically, even while on vacation, and once you set it up there is nothing more you need to do.


If you didn’t do it when planting, put down a 2 to 3-inch layer of coarse organic material over the root zone as mulch. This could be bark chips, shredded wood, shredded leaves, garden compost, or even straw. Not only does it reduce or prevent the growth of weeds, mulch keeps the soil cool, stimulating root growth, and it slows down the loss of water directly from the soil. Keep it clear of the stems and foliage and cover an area a couple of feet wide at least. You will probably need to renew it after a couple of years – it depends on the type of material you used. Once the plants grow and spread outwards the leaves that fall inside the plant will act as natural mulch, and you won’t need to do it anymore. Remember not to dig old mulch into the ground, as more woody kinds of materials rob the soil of nutrients as they rot down.


Your new Thuja Green Giant plants don’t yet have extensive root systems, so they can’t reach the nutrients in the surrounding soil. To keep them growing at their peak speed it is best to feed them for the first couple of years with liquid fertilizers, as these soak right down into the root ball, so the nutrients are available. The foliage can also absorb them directly, so some types can be sprayed directly onto the foliage. If you are unsure, use a half-strength mixture for the foliage, and full-strength on the roots. Once a month is usual, although you might get slightly better growth with half-strength every two weeks. Make the last feeding in mid-September, so the plants harden-off a little before winter comes. Choose a formulation that is blended for evergreen trees and that contains iron and other micro-nutrients. You will really see the difference with liquid feeding, no matter how well you have prepared the soil. That good soil preparation will pay off in future years, but it doesn’t have a big impact in the first season.


Although you want maximum growth, you also want to develop good structure in a hedge, so that it is durable and lasts for many years. So if you are planning a hedge you will clip regularly, start doing it the first season. Just take an inch off the top a couple of times through the season, and a little off the sides too, especially in the upper part, so that your plants slope inwards a little. Don’t be tempted to trim 90-degree sides. It doesn’t work well, as the lower branches will become thin over time, and you will lose that great lush greenness right to the ground that is the mark of a top-quality hedge. These light trimmings as the plants grow produce a dense structure that is resistant to storm damage, and won’t break under the weight of snow. Stop trimming in mid-fall, so that the growth slows naturally before the winter comes, to eliminate the risk of the tips burning if the weather turns cold suddenly.


These are all easy jobs, that don’t take long, but they pay off in spades, with top-speed growth, rich, healthy green foliage, and the best-looking plants around. Good care in the early years of Thuja Green Giant helps it become the great plant you want – it’s easy, so enjoy the summer.

You took the big step and planted a new screen or a hedge of Thuja Green Giant, right? Or maybe you have used some as future large specimens in the corners of your garden. Whichever it is, you have made the right choice if you are looking for fast-growing, disease and pest free plants, that even deer leave alone. These first years are the most important ones, because after that your plants will be almost completely self-maintaining, unless you are planning to trim them regularly for a formal look. It’s during these years, especially the first season or two, that the foundations of an easy and successful future for your plants are laid down.

For the Best Growth of Your New Trees:

  • Water regularly – it’s vital
  • Fertilize properly – use liquid formulations
  • Trim right away – establish dense growth early

We will assume you did all the early steps properly – ground preparation, correct spacing, and good planting – but if not, you will find blogs on this site covering all these things in detail – assuming you haven’t actually put them in the ground yet. Here we are going to consider the important steps in caring for your new Thuja Green Giant plants for the first season or two, so they really get going with a bang.

Keep Watering

The biggest mistake made is to think that because these are tough, reliable plants, you can just plant them and forget them. Maybe you will get lucky, with good falls of rain spaced out nicely through the season, and everything will be fine if you ‘plant and walk away’. But it’s much better to give some simple basic care until your trees become established, and watering should be at the top of the list. Remember that your plants went into the ground with just the soil from their pots around their roots, and for the first little while that is the only soil available to them. So when the weather turns warm and dry, and the summer sun begins to shine, they will start to lose water from their foliage immediately. The only source for that water is the soil around the roots, although if you have planted well, and firmed the soil around the root-ball, that ball will suck some water out of the surrounding soil too. None the less, even if the soil looks damp, it pays to look after that root ball with a little extra care, until enough time has passed for the roots to grow out.

So once a week, or even twice a week if the weather is hot and dry, go along the row with a hose and let plenty of water trickle down close to the stem, soaking that hidden root-ball. Any excess will drain out into the surrounding soil, and this simple exercise, which doesn’t take long, is the best single thing you can do to guarantee the survival and good growth of your new trees.

Pay attention to the surrounding soil too, as the roots won’t grow out into dry earth. The best way, and the most water-wise, is to run a porous hose along the row of your new hedge, weaving it in and out of the stems as you go. This can stay in place for years, and it will quickly be hidden by new growth. By running the water directly on the ground, you get it exactly where needed, and you don’t lose it to evaporation, which happens with a sprinkler. Connect this trickle hose to a regular line, and turn it on for a few hours, until the water has soaked in and spread sideways. How often you need to do it will depend on the type of soil you have, how hot it is, whether you have used mulch (which is recommended), and how much rain has fallen. Don’t be fooled by light showers – scrape back a little soil to see if it is dry underneath, as it often is after light rain. Keep the soil damp, but don’t water until the soil is looking a little dry, as the roots won’t grow into a swamp!

Use Fertilizer

You probably enriched the soil when you planted – it’s highly recommended – but until the roots grow out that food is not available. Plants grown in containers are fed regularly with liquid fertilizers, and you will get the best growth from your new plants by doing the same. Choose a water-soluble formulation designed for hedges and evergreens, and use it as directed. If the directions are to apply monthly, you will get even better results by halving the concentration and applying every two weeks instead, as this gives a steadier supply of those vital nutrients. Start in mid-spring, as soon as you see signs of new growth, and flowers coming out around the garden, and keep feeding into early fall. Then stop, especially in colder areas, as you want your trees to finish growing in time for the new growth to harden off before winter. In warmer regions you can continue feeding until late fall.

Start Trimming Right Away

Since you want your plants to grow as much as possible, trimming might sound counter-intuitive. Some people wait until their plants have grown to their intended size before beginning to trim, but this is a mistake that can shorten the effective life of your screen or hedge significantly.

The best practice is to trim lightly almost as soon as you plant. Once you see a little new growth, take a sharp pair of shears and trim a little bit off. It doesn’t even have to be an inch of growth, and pay special attention to the top, as it will soon ‘run away’ if it can, leaving the bottom areas thin. This is something that cannot be fixed later, so slow down growth in height just a little, to build up bushy, broad plants that will stay green to the ground for decades. In fact, if your new plants have some wispy long upper growth, trim it back a few inches the same time that you plant.

Your goal should be broad, full plants with many branches right to the ground. Regular light trimming, taking a little more from the top than the sides, will make that happen. Taper the growth inwards a little, so that light reaches right to the bottom, and always do that for the life of your hedge and screen. During the first and second seasons you might want to trim lightly 4 or 5 times during the growing season, and since your plants are still small it won’t take long. Use sharp tools and just remove the tips from the new growth.


These simple steps are just a little extra work but a big investment in a great future for your plants. Your new Thuja Green Giant are going to do most of the work, so give them a helping hand – it’s a small effort that brings big results.

As spring slides into summer, those who didn’t do everything they planned for spring start to worry. Is it now too late? Will I have to wait until fall or next spring to do that planting in the garden? Specifically, I am planning to plant a screen or hedge of Thuja Green Giant – am I now too late?

The traditional planting seasons of spring and fall were connected to the traditional way that plants were grown in nursery fields. When they reached a saleable size, they were dug and usually wrapped in burlap, or put into temporary pots, before being sold and then replanted. These things must be done at the right seasons, and trying to dig and plant in summer was something doomed to failure, because a large part of the active root-system is left in the ground.

Nursery methods have changed a lot, and today plants like Thuja Green Giant are grown for most or all their lives in pots. This means there is no root disturbance when they are moved around, and they arrive at your home with 100% of their root system intact and healthy. So the simple answer to planting is that today we can plant almost all year round, as long as the ground is not frozen. There are some good reasons for not planting in the depths of winter, but the situation for summer is much easier. Summer planting is not only possible, but easy and successful, as long as you take some simple precautions. Let’s see what those precautions are, and then you will be ready to plant that screen or hedge you have been planning – no matter what season it is.

Tips for Summer Planting

  • Prepare the area well, and water it thoroughly the day before
  • Be sure the plants have been water well before taking them out of the pots
  • Water deeply when planting
  • Mulch the root-zone to reduce water loss
  • Water close to the trunk every second or third day for the first weeks

Preparing the Planting Site

Just as for any other season, preparing the ground for planting should be top of your list. Most failures can be traced back to poor preparation. Digging a pot-sized hole in hard ground, and then pushing the plant into it, is always going to give bad results, even for tough plants. Instead, dig the whole row you are planting in, to a width of at least 3 feet. Incorporate plenty of rich organic material, to hold water and feed your plants.

If the ground is dry it may be hard to dig, so you should water the day before you dig or till. Once it is all ready to go, water thoroughly again the evening before you are going to plant.

Preparing the Potted Plants

When your new plants arrive, you may not be ready to plant right away. Remove all the packaging, and then place the plant in an area shaded from the afternoon sun. Plastic pots, especially black ones, absorb a lot of heat from the sun, and this damages the roots. If you do have to leave the plants in the sun, arrange them in a block so they shade each other, and then put something over the pots on the south and west side to protect them from direct sunlight. Burlap, some broad planks, mulch or loose soil are some possible materials you could use.

The biggest risk when planting in hot weather comes from handling plants with dry root balls. The soil can fall off, the roots rapidly become desiccated once outside the pot, and there is a real danger that the root ball will still be dry after you have planted and watered them. So always water the pots thoroughly the evening before planting. If you have to water them just before planting, go ahead – the only problem with that is the soil is wet and so makes more mess.

Water Deeply When Planting

You should still cut through the circling roots around the root ball in two or three places – it doesn’t hurt, and it encourages the roots to grow outwards, which is what you want. The commonest way people plant is to fill the holes completely and then water the area. A much better method, especially during summer weather, is to put back half to two-thirds of the soil, firming it down around the root ball. Then fill the remaining space with lots of water, and wait until it soaks down. This simple trick makes sure that plenty of water is available around the roots, where it is needed, not in the top few inches, where the roots can’t reach it. If you are forced to plant into dry soil, then do this soaking twice, so that the water spreads outwards too. Once the water has drained away, put back the rest of the soil, and once all the plants are in, go around and give them a final soaking.

Mulch the Root Zone to Conserve Moisture

Applying mulch over the root-ball zone of newly planted trees is always the right thing to do, but even more so in summer. It will keep the soil cool, which encourages root growth, and it reduces water-loss from the soil surface, reducing the risk of the soil drying out. Cover the soil further out than the width of the root-ball, because you want to create a cool, moist environment that the roots will want to grow into. Apply a layer 3 to 4 inches thick and keep it a few inches away from the stem and foliage.

Keep up the Watering

The biggest risk with summer planting is the rapid drying of the root-ball because of high rates of water loss from the foliage. Warm weather encourages growth, and it also increases the rate that water is lost from the leaves, especially from soft new growth. The only water available to newly-planted trees is in the soil that the roots are in, which is a small volume. So that moisture can be removed in a day or two. Water will be drawn into that soil from the surrounding earth, especially if you have firmed it down properly, but it may not happen fast enough. Because you see the soil surface looking damp, that doesn’t mean the hidden root-ball is. For the first three or four weeks, water every second or third day by letting water trickle down close to the stem of each plant. That way you will keep that root-ball damp. Water the surrounding soil too if it starts to look dry, because you want the roots to grow outwards, and they won’t grow into dry soil. Once the plants are established, you only need to water the whole area, as normal.


If you follow these simple tips, which are just good gardening habits, then summer planting of Thuja Green Giant is as easy as relaxing on those gorgeous summer days and watching your plants grow.

There is no question that among evergreens, Thuja Green Giant is the most recommended and the most popular of them all. When it comes to rising to the top of the poles, it’s a case of, “May the best plant win”. So what qualities does this plant have that allowed it to rise to the top? In answering that question, we can learn more about this plant, its suitability for your garden, and what it is about it that has proved so successful. Now read on. . .

The Origins of Thuja Green Giant

When we think of famous places for producing plants, Denmark is not a country that immediately comes to mind – yet it is there we begin our story. Dorus Poulsen was a keen amateur botanist and gardener, and in 1878 he started a nursery, growing and selling plants, near a grand manor house called Frijsenborg. There he became known for his rose breeding, and the Poulsen name was associated with quality and innovation. When Dorus retired in 1925 his sons took over the nursery, and it was probably one of them, who, in 1937, found a seedling that would eventually become famous. Here the picture is a little murky, because we don’t know if this was something produced by a breeding program – the Poulsen family were all keen on plant breeding – or just an accidental event that caught their keen eye. In any case, within a short time World War II would engulf Europe, and seedling evergreens were not of much importance in that life-or-death struggle.

It is 1967 before we pick up the trail again, now at the National Arboretum in Washington D.C. They received a shipment of plants from a Poulsen nursery – the company now had a number of branches- in Kvistgaard, north of Copenhagen. There were several different plants of Thuja evergreens, and these were planted out for observation in a nursery area. Several staff members noticed the speed of growth of this plant, which was very rapid in the early years, and in 25 years this plant was 30 feet tall – a remarkable achievement. In the early 1990s people were starting to pay attention

What is Thuja Green Giant?

So what was this plant? The botanists could see that it was a Thuja, a relative of the eastern Red Cedar, which is a common plant throughout the north-east. Because of its vigor and rapid growth, they suspected it was a hybrid – a cross between two natural species – but they didn’t know. The records didn’t help much, and beyond tracing it back to that Poulsen plant found in 1937, they didn’t have much to go by.

However they now had DNA analysis available, a great tool for solving these kinds of mysteries, and using that a team of scientists from the major American botanical gardens figured out what they were dealing with. This mystery plant really was something remarkable and never seen before – a hybrid between the Western Redcedar, Thuja plicata, and the Japanese Arborvitae, Thuja standishii.  One grows in Oregon and Washington state, and the other grows in Japan. We may never know exactly what happened in that nursery in Denmark 80 years ago, but it produced a trans-pacific hybrid, full of what plant breeders call ‘hybrid vigor’.

Why Does Thuja Green Giant Grow So Fast?

When two plants are bred together, all the best forms of the many genes it has hide the bad forms, that naturally accumulate over the millennia. So a hybrid plant is running on all cylinders perfectly, creating this hybrid vigor, and this is the simple explanation of why Thuja Green Giant grows as fast as it does. Growth rates of over 3 feet a year have been seen in young plants. In a trial at the University of Arkansas, tiny plants grew 10 feet tall and 5 feet wide after only 7 years. This was a trial of many hedging plants, and the fastest was the Green Giant. This is the major reason for the popularity of this plant – its growth rate. If you need large evergreens in a short time, then Thuja Green Giant is the number one choice – right on top of the list.

Deer Don’t Touch It

Deer are a serious problem for some gardeners, and they can and do decimate plantings. Some kinds of Thuja are popular winter food, and a hedge or screen can and is often stripped completely of its lower branches – ruining the work of decade or more.

Deer are very unpredictable, and when driven by hunger will eat just about anything, so it’s impossible to make an absolute statement, but the evidence is that Thuja Green Giant is almost always left alone. Spraying with a deer repellent in winter, especially when plants are young, is always a good idea, but compared to other Thuja, deer resistance is another reason why Thuja Green Giant is at the top of the polls for large evergreens.

Lack of Pests and Diseases

That hybrid vigor that produces such rapid growth also protects Thuja Green Giant from any serious pests or diseases. This is unlike some other evergreens, and one reason for the success and popularity of this plant is its usefulness in replacing old hedges that have become diseased

How Winter-hardy is Thuja Green Giant?

If you live in zone 5, or anywhere warmer, then there is no question that this plant will thrive, and it will survive winter in a perfect green state. If you have heavy snow, then any evergreen needs to be trimmed from time to time, so that it doesn’t have long side branches that can bend and break under wet, heavy snow. But as for winter burn, browning, or the bronzing that plagues some evergreens, those will not be a problem.

If you live in colder zones, then Emerald Green Arborvitae is a better choice. It’s hardy to zones 2 or 3, making it a top choice. At the other end of the scale, if you live in zone 9, or in a hot, dry area like Arizona, then the Italian Cypress is the best choice. It’s still fast-growing, and it is acclaimed for its drought-resistance.

Looking at these things -from growth rate to hardiness – it’s easy to see why Thuja Green Giant has risen to the top of the list for larger evergreens, whether you need an informal screen or a trimmed hedge. Just remember that it does get large, so don’t use it for hedges less than 6 feet tall, or plant it in narrow spaces, or too close to buildings. It’s a great plant, but sometimes something smaller is a better choice!