Thuja Green Giant is deservedly popular. Fast-growing, drought and salt-spray resistant, generally avoided by deer and free of pests – what more can we ask of an evergreen? You may be planting a screen, or a more formal hedge, or using it as upright specimens around the garden. Whatever your need, its easy to see why this plant remains consistently popular across a large swathe of the country. Good results though, come from good beginnings, and with Thuja Green Giant – and of course with most plants – that good beginning is the planting procedure. If you are new to plants, or indeed if you have some experience but could always learn more, let’s look at the steps and stages of planting, so that your trees get off to the best possible start.
Even the best plant can only grow as well as the soil it is in. While it is probably possible in many gardens to just stick it in the ground and walk away, the best results – especially rapid growth and good establishment – depend on planting into prepared soil.
There is no particular secret to good soil preparation, and no matter what type of soil you have, the key steps are digging and enrichment. In a natural soil nutrients and finer particles are carried downwards by drainage water, so that the upper layers have fewer nutrients than lower down. Just as in farming, digging and turning the soil is a vital first step in improving the quality of your soil. For smaller areas, or just to plant one or two trees, hand digging with a spade will do a great job in a reasonable time.
For a larger area, renting or borrowing a roto-tiller will save a lot of work. Get the biggest machine you can handle, and that will fit into the area you are working with. The biggest issue with using roto-tillers is to get the necessary depth. The soil needs preparing up to 12 inches deep, or at least to the depth of a full-sized spade, and a roto-tiller can easily skip across the surface, making the area look great – until you discover that it has only gone down a couple of inches. The trick is to go over the area a couple of times at least, until it buries itself as deep into the ground as it can go. Then you know you have done the job.
Adding Organic Material
Find a source of rich organic material. This could be garden compost, rotted farm manure (cow, sheep or horse), spend compost from a mushroom farm, well-rotted leaves, or perhaps some other local alternative. Although peat moss has been widely used in the past, it isn’t really a top choice, and the environmental damage done by harvesting peat is another negative – but if it is all you can find, so be it.
After a quick first pass with the tiller, spread a layer at least 2 inches deep, up to 6 inches deep, and till it into the ground as you work the tiller deeper. The great thing about organic material is that it improves all kinds of soil. With sandy soil you will see an improvement in water retention and nutrients, while in a clay soil the same material increases drainage and allows more air into the earth, speeding up nutrient release. For a hedge, prepare an area about 3 feet wide, and a circle of similar diameter for an individual tree. It is better to create a continuous bed of prepared soil for a hedge or screen, rather than just make individual spots for each plant. In average garden soil you don’t need to add other nutrients, but in poor soil it pays to use a starter fertilizer as well, raked into the ground after tilling it.
When planting hedges and screens, the temptation is always to put the plants close together, to get instant coverage. This is a mistake, since crowded plants can’t develop properly, and will compete with each other. This easily results in some plants dying, and in all the plants growing tall but spindly. You won’t get the broad, dense hedge you are looking for, and the lower branches will soon die, leaving you with a collection of bare stems with leaves on the top. For Thuja Green Giant, allow at least 3 feet between each plant for a hedge, and up to 8 feet for a screen. This plant will become 12 feet wide in 10 or 15 years, so it will soon fill such relatively small spaces. By allowing enough space you keep the plants green and thick right to the ground, which is almost always what we want to see. Remember too to allow at least 3 feet back from a fence, wall or property line. You want to keep your trees on your side of that line, so they remain yours and don’t spread onto your neighbor’s land.
When it comes to the actual planting procedure, remember to water the pots thoroughly the night before, and the ground too if it is dry. Never plant dry pots into dry soil. Dig holes into your prepared ground just a little wider than the pots, and the same depth. For a hedge, it is easier to get the spacing right if you take out a trench, rather than individual holes. That way you can line everything up, adjust the spacing to get it all even, and then plant – the result will be much better from the get-go.
Once you have the holes dug, slide the plants out of the plastic pots. To encourage the roots to spread outwards, and to prevent future problems with roots circling around and strangling the trunk, you need to open up the root ball. The simplest way is to take a sharp knife and make three or four long cuts, from top to bottom, one-inch deep down the sides. If most of the roots seem concentrated at the bottom, instead make a cross-cut on the bottom of the root-ball, again about one-inch deep. This might sound drastic, but your plants will thank you for it in the years to come.
Place the root-ball in the hole and adjust the depth so that the top is at the same level as it was in the pot. If your soil drains slowly, raise it up a couple of inches. In very poorly-draining soil, it is a good idea to build a low mound along the planting row, about 8 inches above the surrounding area, and plant onto that. This can really make a difference.
Once you have the trees in place, replace about two-thirds of the soil, and firm it down around the root-ball. Then fill each hole to the top with water and wait for it to drain away. This is far better than watering after you plant, as the water is down around the roots where you want it. Once the water has drained away, replace the rest of the soil and firm it gently. Remove any tags, string or stakes, and rake the soil level. If you are planting in spring or summer, putting a mulch over the roots is a good way to conserve moisture and encourage growth. You can use some of the same material you added to the soil. A layer 2 inches deep, kept a few inches away from the stems and off the foliage, will do the trick. Renew this every spring, or every second spring.
That’s it. You are done. Your plants of Thuja Green Giant are off to the perfect start. Now all you need to do is stand back and watch them grow.