There is an old saying: The best time to plant a tree was 20 years ago. The second-best time is now.
Planting a tree is symbolic, a statement of permanence and longevity. It can even be a legacy to leave behind. And if you have little ones, plant a tree now and watch them grow together.
Perhaps that is sentimental. But there are other, more practical reasons to plant a tree. Trees are great for the environment, taking in pollutants and carbon dioxide and giving out oxygen. Their roots support soil structure and take up plenty of rainwater.
And trees are fantastic for garden design. They give height and act as an anchor in the planting scheme. The canopy provides shade, privacy and leafy green colour, plus autumn interest as the leaves change colour. Plus trees are great habitats for wildlife and birds.
So here are my top gardening tips on how to plant a tree in your garden.
Choosing the tree
Acer (Japanese maple)
Before you buy your tree, it makes sense to do some research. The most important factor is space. There is no point planting a small young tree if, in five years’ time, it dwarfs and smothers everything in the garden.
Look for the eventual or fully grown size and check that fits with your garden and space. Also bear in mind that large trees have very large root systems, which are no good if you have poor, shallow soil.
You also need to check soil and sunlight levels. Most soil types should be fine, and a sheltered but sunny spot is usually best.
I would also advise choosing something that looks great for long periods of time, especially if you have a small garden. Magnolias look beautiful in spring but boring the rest of the year. Look for spring blossom, vivid autumn colour or winter berries and pretty bark.
You can also grow a fruit tree – apple trees have blossom in spring, leaves all summer and masses of fresh fruit in the autumn. Perfect!
How to plant a tree
Step 1 Prepare the ground
Choose a dry day when the ground is not frozen or waterlogged. Bare-root trees should be planted during dormant season from late autumn to early spring – get more bare root advice here. Container-grown trees can be planted all year round. Water the tree well on the day of planting.
Dig a hole as deep as the rootball and two to three times as wide. If you garden on heavy or clay soil, dig a square hole rather than a round one to help roots spread more easily as they grow.
Contrary to common advice, you should not add fertiliser or organic material to the planting hole. There is no evidence to suggest that they boost the tree, and they may even hinder new root growth. Extra nutrients are better applied as a mulch after planting.
However if you garden on poor soil, add a sprinkling of mycorrhizal fungi (often sold as Rootgrow) which is known to boost root growth.
Step 2 Plant the tree
Remove the tree from its pot or wrapping and place it in the hole. Spread the roots out and settle the tree so that the first flare (top layer) of roots sit level with the soil surface.
This is important because planting a tree too deeply prevents air from getting to the roots and may rot the stem, damaging or even killing the tree.
For container-grown trees, you may need to scrape the soil off the top of the rootball to find the first flare. Lay a garden cane across the hole to find ground level and settle the tree, adding or removing soil so it sits at the right depth.
Carefully backfill the hole with soil in layers, firming in gently until the soil is level. Avoid pressing down too hard and compacting the soil – it should not feel solid.
Step 3 Stake and water
Any stem or trunk that is thicker than your thumb will need staking. A newly planted tree does not have a deep enough root system to protect it from being pulled out by strong winds.
You should push a stout wooden stake into the soil just outside of the rootball, leaning backwards at a 45 degree angle to meet the trunk. Make sure the stake is deep and firmly fixed in the soil – use a wooden mallet to drive it in.
Then gently tie the tree to the stake using soft tree ties. Make sure the ties do not cut into the stem as it grows – keep loosening them.
Water the tree
Water in the tree really well. One of the most common problems with newly planted trees is drought. Water every few days during dry spells for the first growing season.
You should also water deeply rather than little and often. This pushes the water deeper in the soil, encouraging the tree to grow deep roots and making it more drought-resistant.
Warm, dry and windy weather is the worst for drying out trees. So watch out for drying and water the tree as much as possible. Current guidelines suggest you need to pour on four to six watering cans’ worth per square metre every week on normal soil.
For heavy or poor-draining soil, you may not need to water as much in case you cause waterlogging. The symptoms for drought and waterlogging are often the same, so if you’re not sure, dig next to the rootball with a trowel to check the soil is draining.
Aside from watering, it is important to keep the soil around the tree clear of weeds. They grow roots near the surface, taking up vital water before it gets to the tree.
You can put down a layer of mulch (compost, well-rotted manure or rotted bark chips). This helps retain moisture and smother weeds. Just make sure to leave a 10cm ring around the stem clear, to avoid rotting the wood.
If rabbits or deer are a problem in your area, buy tree guards and spirals to protect the bark.
Don’t feed the tree during the first season, but you can use general fertiliser to give it a boost during the second year. However, this should not be done if you have applied mycorrhizal fungi, as the phosphorous levels inhibit fungal growth.
Check the tree ties every spring and autumn and loosen as needed. After two growing seasons the stake can be removed.
David Domoney is a Chartered Horticulturalist, Broadcaster, and Author. David has worked with a number of the UK’s leading garden retailers as a plant buyer and strategic consultant. With more than 30 years experience, in horticulture, David is as passionate about plants now as he was when he bought his first plant at a village fete.