Monthly Archives: July 2019

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.

Now that we have entered the summer months, the spring planting season has drawn to a close. That doesn’t mean that we need to stop planting. One of the great benefits of plants growing in pots is that they can be planted at any time of year.

This is very different from 30 or 40 years ago, when a lot of plants – evergreens in particular – were grown in fields and dug out of the ground in spring or early fall, and then sold for immediate planting. This change doesn’t mean, though, that we can treat summer plantings the same way as we might a spring or fall planting. While bargains are often available in summer, as nurseries clear their remaining spring stock, they can need some additional care, if they are to succeed, and not suffer any set-backs. Let’s look at the way to handle summer planting of evergreen bushes, such as Thuja Green Giant, Emerald Green Arborvitae, or any of the multitude of ornamental evergreens available to us.

Care of Evergreens Before Planting

Once your evergreens arrive home, either from a shipping delivery, or from a shopping expedition to a garden center, you need care. In spring or fall we can often just put them in the garden for a few days, and more-or-less leave them to their own devices. Not in summer.

Shade is best

Find a shady spot in your garden, and unwrap the plants immediately, including any string that has been used to hold them together during shipping. If you have bought several, perhaps for a hedge or screen, then space them out a little, so that the air can circulate around them. Close packing can lead to yellowing, or fungal diseases.

Water regularly

Water the pots thoroughly, so that water drains out through the holes in the bottom of the pot. Do not stand them in saucers – let the water run away into the ground. If you are not planting for a few days, check the root balls each day, and water if the top inch is dry.

Shade the pots

Sometimes, in a new garden, you may not have a shady area available, since you have no large trees yet. There may be a zone of shade along a fence, or on the north-facing side of your house, but if not, then place them in the sun. In this situation the foliage will normally be fine in full sun, but there is a danger that the pots, which are usually black, will absorb a lot of heat from the sun’s rays. This can raise the temperature inside the pot, damaging the roots. In this situation, wrap some old burlap, or some scrap cardboard, around the pots. If you have lots of plants, arrange them in a block, and put some shading on the south and west sides, which will be the ones that pick up the most heat. Cardboard, or some burlap attached to sticks works well, and so does white plastic sheeting, which will reflect the heat away.

Planting Evergreens in Hot, Dry Weather

Now you have taken care of your plants for the time you need to start planting, we can look at the planting site, and modifications to planting when you are doing it in the summer.

Preparing the planting area

In spring or fall there is usually enough rain around to mean that the soil you are planting into is damp. Often in summer it won’t be, but instead the area will be dry. For good establishment of your plants it is best if the ground is damp, so a day or two before planting, arrange for a thorough watering of the whole area, not just the planting holes. If you plant into dry soil there will be no encouragement for the roots of your plants to spread out, even more if you keep the root ball watered, so the surrounding soil needs to be damp too.

The best way to do this is to put a sprinkler on the whole area for a few hours. If you stand with a hose you may simply wet the top couple of inches, without their being time for the water to penetrate. By doing it a day or two before planting you leave time for the water to drain down, and you won’t be planting in mud. Especially if you have clay soil, allow two days for it to drain well.

(I am assuming here that you have already dug or rototilled the area and added organic material to the soil, as we have described in lots of previous blogs)

Prepare the plants

The night before you plant, give all the pots a good soak. That was easy!

Planting time is here

Finally, we get to do the planting. Since you have already prepared the area, just remove enough soil to fit the pot. If you are planting into soil that has not been prepared, take out a hole three times the diameter of the pot, and mix some organic material into the soil you removed from the hole. Just dig the hole to the depth of the container, and roughen up the bottom with a digging fork, or spade.

If you are planting several bushes, don’t remove them all from the pots before starting. The delicate roots will dry and burn quickly in the hot sun, or dry wind, and die. Only remove the pot when you are ready to immediately put the plant into the hole.

Put back two-thirds of the soil, and firm it down around the root-ball. Now fill the hole with water, and let it drain away completely. Replace the rest of the soil and firm it down gently.

After you finish planting, water the whole area well, and add a layer of mulch – organic material like compost or manure, or shredded bark, are better materials than gravel and bark chips, as they will feed the soil as they break down, while reducing water loss from the soil surface. Cover an area triple the pot diameter with mulch, leaving the stem and foliage uncovered.

Caring for Newly-planted Evergreens in Summer

Watering

Newly planted bushes are entirely dependent on their root balls for water, until they send out new roots, which can take a month or more. So, in summer, let a hose run gently, close to the stem, for a while, every second day for the first week. The water around the plant over a bigger area twice a week for the first month. After that, water weekly until the end of the season.

Don’t make the common mistake of skipping a watering session because there was a summer thunderstorm. That water rarely penetrates the ground at all – scratch the surface the next morning if you don’t believe it, and you will see dry soil.

Feeding

To help your plants start growing strongly, use a liquid fertilizer for evergreens every two weeks during this first season. In the following seasons you can switch to granular feeds, which are usually cheaper, certainly quicker to apply, and work well on established plants with bigger root systems that can absorb them.

That’s It

If you follow these simple steps, you will have great success with summer planting, even in the hottest conditions, and you can take advantage of the reduced prices that are often available. Don’t put it off until the fall, or next spring – get planting now.