Why plant a tree?
Tree planting is a very rewarding activity. Trees are a vital part of our ecosystem. Without them, life on Earth would be unsustainable. Not only do they look attractive, they help you feel less guilty about all that oil being burnt in your name. Potentially, your tree will spend decades or even centuries growing where you plant it. In a garden, trees are an important design element, providing a permanent framework. Time spent planning beforehand can make the difference between a really healthy tree and a dead one.
Choose a planting site
Trees grow well in sheltered, warm places, and microclimates within a site can vary widely, so find a good position before you start digging. Avoid areas with poor drainage, as waterlogged soil has almost no air in it, which encourages rotting. Make sure the tree isn't going to interfere with overhead or underground wires and cables, the foundations of buildings or drainage systems. It’s a bad idea to plant willows (Salix) or poplars (Populus) in developed areas as their strong roots can damage foundations and drains.
Choose a tree
The soil type, availability of light, the level of shelter from wind and the climate all affect which trees will grow best on your site. Use a good reference book (for those living in temperate zones I recommend the Hillier Gardener's Guide to Trees and Shrubs, ISBN 0 7153 0130 6) to help you decide which cultivar will be most suitable. If, for example, you're organising a tree planting day, and you're thinking of planting trees out in the countryside, it's vitally important that you select an appropriate native species. There is a good argument for growing only native species in a garden, too, as they are the best adapted to the local environment. Local suppliers will stock a range of trees suitable for your climate although other factors relating more specifically to your site need taking into account, for example if your area experiences late frosts, or if you live in a coastal area.
Buy a tree
Trees are sold either in containers, bare-rooted, or root-balled. You can buy them from nurseries, garden centres or by mail order. They are available at different stages of growth. Older trees will create an immediate effect but will suffer more from the disturbance of transplantation and so take longer to become established. They are also more expensive than younger trees, which are quicker to establish a root system and start growing.
When choosing a plant, make sure it has well developed, evenly distributed roots and shoots, and that it is undamaged and pest and disease-free. If you buy a tree by mail order and find it's unhealthy when it arrives, don't be afraid to ask for a replacement. It's easier to do this if you're present when the delivery is made.
Buying container-grown trees
These are easily available and can be bought and planted at any time of year. Some trees, such as magnolias and Eucalyptus, are very sensitive to root disturbance. These are best bought in containers as they minimise stress on the plants. It’s a good idea to have a look at the roots before buying if it's possible to remove the container. Avoid plants which have become pot-bound, where roots have become congested, or those with toughened, old roots straining to get out of the container. These plants will have difficulty in establishing healthy root systems once planted, and will consequently be susceptible to wind damage. Equally, if when you remove the container the compost falls away from the roots, this indicates that the root system is underdeveloped.
Buying bare-root trees
These are grown in open ground and must be bought in
autumn or early
spring. Trees sold bare-rooted are usually
deciduous, and therefore can only be dug up while they’re
dormant. As with container-grown trees, make sure the tree you choose has evenly developed, pest and disease-free roots.
Root-balled trees have their roots wrapped in hessian or other material to retain moisture and to protect them from damage. Make sure this wrapping is still in place when you buy the plant.
When to plant your tree
It's best to plant as soon as possible after buying. If you can't plant the tree immediately, 'heeling in' (planting temporarily- the practice of burying the roots in a hole and roughly covering them with soil) will be necessary for bare-rooted trees, while root balled and container grown trees will wait for a few weeks if kept watered and frost-free.
Container-grown trees can be planted out all year round, but avoid planting in times of
drought or frost.
Bare-rooted and
root-balled trees should be planted between mid autumn and mid spring, avoiding frosts. Wait until mid spring to plant half
hardy varieties.
Alternatively, wait for your country's National Tree Planting Day. This is August 27 in the States, July 28 in Australia, and the UK has an entire Tree Week at the end of November.
Dig a hole!
Digging a hole sounds simple, but getting this right is crucial to the tree's success. It's also very hard work, and if you are unfit or suffer from back pain I strongly recommend that you hire someone to do this.
Taking the final position of the tree as the centre, mark out an area three or four times the width of the rootball. Dig out this area to a depth approximately one and a half times that of the rootball. Mix the removed soil with organic matter, such as well rotted manure or garden compost. If you want to stake the tree, the stake should be put in place at this point. The stake should be positioned off centre, on the side of the prevailing wind.
Planting the tree
First, thoroughly
soak the rootball. You may need to stand the container in
water for a few hours if the soil has dried out completely. If containerised or root-balled, remove the packaging carefully. Gently
tease the roots free to encourage balanced growth.
Prune back any damaged roots.
You should be able to see the previous soil level by looking at the base of the trunk. This is called the nursery mark. To achieve the correct planting depth, get someone to hold the tree in place, lay a cane over the top of the hole and then add or remove the soil until the nursery mark is level with the cane. Keeping the tree in position, fill the hole with the mixed soil and organic matter, firming it as you go to make sure the roots are all in contact with soil. If you're staking the tree loosely attach it to the stake using one or two plastic ties. Lightly prune, removing any dead, damaged or diseased wood. The tree will need plenty of water at this stage; after watering, cover the exposed soil with a thick layer of mulch, such as chipped bark.
Aftercare
Water the tree regularly for the first two years, after which time it should have established sufficient roots to get the water it needs from the soil. Renew the mulch in the spring to help keep down weeds, which compete for water and nutrients. It may be necessary to place a tree guard around the the trunk to proctect it from bark-stripping animals such as rabbits. This also deters cats, who may view your new tree as a scratching post.