What Are Trees?

Trees often form the heart of a good garden design. They can be stand-out features that really make a huge difference in a garden.

Of course, when we talk about trees, we are talking about, in botanical terms, a perennial plant with a woody, elongated stem or trunk. These amazing lifeforms have been in existence for 370 million years. They play a vital role in nature’s cycles on our planet, and are essential for the survival of our species, and all life on Earth.

As you are no doubt already aware, planting a tree in your garden is a wonderful thing to do for people and planet. As the old adage goes – the best time to plant a tree was twenty years ago. The next best time is now.

We often tend to view trees simply as the backdrop for our daily lives. We may not have given much thought to the many ways in which they enrich and improve the environments around them. But in their own quiet ways, trees are working away as autogenic ecosystem engineers. They work on the environment around them through a wide range of complex mechanisms. They:

  • Turn energy from the sun into the oxygen we breathe.
  • Sequester carbon, helping in the drawdown necessary to combat our climate crisis.
  • Play a crucial role in the world’s water cycle, and alter atmospheric humidity and rainfall.
  • Help us catch and store energy, and make the most of natural, renewable resources.
  • Play a vital role in managing water flow in a landscape, and managing soil erosion and nutrient loss.
  • Provide shade and protection for the soil.
  • Drop leaves and increase surrounding soil fertility.
  • Provide leaves/ twigs and branches that can be used elsewhere in the garden for fuel needs or to maintain fertility.
  • Shade us from the sun, creating pleasant, shaded recreational areas.
  • Filter winds and reduce exposure on a site.
  • Clean the air of dust, air pollution gases and other airborne contaminants.
  • Provide valuable yields. Trees can provide wood, fruits, nuts, flowers, edible leaves, medicines and other resources for humans.
  • Are a source of fodder (and give shade) for livestock.
  • And provide food, shelter and habitat for a huge range of wildlife.

Planting trees is essential for a sustainable and ethical future. And planting a tree or trees in your garden is one way that you can play your part in forging the future we all want to see. They can also benefit you in a range of personal and direct ways.

Trees are truly remarkable things. And no matter how large or small your garden may be, it is likely that you will be able to include at least one in your space. Trees can be grown:

  • Within an orchard or forest garden food-producing system. (An easy and relatively low-maintenance way to grow your own at home.)
  • As part of a mixed hedgerow with shrubs, or in a shelter belt scheme.
  • As single, free-standing individual specimen trees (a fruit tree with its companion planting guild, or a beautiful shade or ornamental tree, for example.)
  • Trained against a wall or fence, or pleached.
  • In containers (there are patio trees on dwarfing rootstocks that can be grown in even the smallest spaces).

There are a huge number of trees to choose from, so you are sure to be able to find at least one suitable for your particular garden.

Popular Trees Grown In The UK

There are of course a huge range of trees grown in the UK, but here are some of the most popular options:

How To Plant A Tree

If you would like to plant a tree in your garden, the first and most important job is to choose one. In order to choose a tree you need to think about:

  • The conditions in your garden, and which trees will thrive in that particular location. Be sure to think about sunlight and shade, temperatures, exposure, water and the soil (if growing in the ground).
  • What exactly you want from the tree – for example, how large would you like it to be? Would you like an edible yield? Should it provide privacy or shade? Do you want something to provide year-round interest? Do you want something that is great for local wildlife?… decide your primary goals before you decide on a tree for your garden. Make a list of what you want before trying to find a tree that matches up.

Fruit trees for gardens are often a popular choice. But it can also be beneficial to include plenty of other trees, especially native trees that have benefits for local wildlife. Remember, if you choose nitrogen-fixing trees, (alder, laburnum…) these will help make sure the nitrogen in your garden is replenished.

Just five blossoming trees can produce as much nectar for pollinators as an acre of meadow. There are plenty of reasons to choose certain trees. If you have your goals clear in your mind it will be easier to make the right choices.

Once you have chosen a suitable tree, it is time to plant it. It is best to plant a tree between October and March.

  • Prepare your growing area and dig a hole three times as large as the roots of the plant or pot it came in and the same depth.
  • Whether your tree came in a pot or as a bare-root plant, soak the roots thoroughly in water.
  • Tease out the roots and loosen tangles, spreading out roots to encourage them to grow into the surrounding soil.
  • Place the tree into the planting hole, and make sure that the soil surface is level with the point where the roots meet the trunk.
  • Consider adding mycorrhizal fungi around the roots to aid the tree in establishment.
  • Make sure the tree is upright, and that you are happy with the orientation.
  • Refill the hole, making sure that you do not leave any air pockets, and damp down the soil around the tree firmly but carefully.
  • Consider adding a tree guard or spiral to protect your new tree.
  • Water the tree in well and add an organic mulch 5-8cm thick around the base. But make sure you keep the mulch away from the base of the trunk.
  • If the tree requires it, add a stake, hammering it into the soil at a 45-degree angle. Tie the tree to this support.

What Do Trees Need To Grow?

Like other plants, trees need sunlight for photosynthesis. Though some trees need more sunlight than others.

They also need carbon dioxide from the air. Through the process of photosynthesis, they take in CO2 and expel oxygen.

Of course, trees also need water. Water enters the trees through their roots and carries essential nutrients nitrogen, phosphorus and potassium, as well as a range of micronutrients.

Nitrogen is essential for photosynthesis to take place. It is important for the formation of tissues and cellular growth, and helps form chlorophyll. Phosphorus boosts plant growth and stimulates roots, is important for flowering and fruiting, and increases a tree’s resistance to disease. Potassium is also important for flowering and fruiting, and, amongst other things, regulates the uptake of CO2 during photosynthesis.

Other important nutrients required by trees are calcium, magnesium and sulfur, and micronutrients including iron, manganese, zinc, copper, boron, silicon, and molybdenum, which are needed in much smaller quantities.

Trees need the soil, with its complex web of micro-organisms like fungi, bacteria etc., to function as it should in order to absorb water and nutrients through its roots. In healthy soil, all the different elements of the soil web work together, transporting water and allowing nutrients to disperse, and travel where they are needed.

Trees grown in containers, without contact with the soil web, will get some water and nutrients from the growing medium. But will typically require more watering and more feeding than trees grown in the ground. It is always best to allow trees to grow as part of the ecosystem, rather than in containers, where possible.

pine cone tree covered in snow

What Conditions Should You Avoid?

All trees should be carefully chosen and you should make sure that you do not place a tree in a position that is not suitable for that particular type. Make sure that you avoid placing a tree that is too large and vigorous for the space, and consider the proximity of the tree to structures, and to other plants. Make sure you know how large it will ultimately grow.

Ideally, you should position a tree where it can remain for years without being disturbed, and continue to sequester carbon and provide other benefits for the future. Take care not to position a tree where it might pose a threat to your or your neighbour’s property, or where roots could do damage to underground pipework or septic systems.

Frequently Asked Questions

How Long Does It Take For A Tree To Grow?

How long a tree takes to grow depends on which type of tree it is, and the conditions in which it is grown. The answer to how long it takes for a tree to reach maturity can vary considerably. It water abundant tropical zones, trees can often be fully grown in around 30 years, while in cooler regions it might take several hundred years to reach maturity. Trees will often be shorter and grow more slowly if ideal environmental conditions are not met.

The lifecycle of a tree begins with the germination of the seed. Seeds become seedlings, and then become known as saplings when they are over three feet tall. Trees with longer lifespans like oaks and yews are saplings for much longer than shorter-lived species. During the sapling phase, trees typically have flexible trunks, smoother bark than mature trees, and are unable to produce flowers or fruit.

A tree is defined as mature when it starts producing flowers or fruits. This is when the tree is at its most productive. How long it will stay in this phase also depends on the species, and can also vary significantly.

For example, English oaks typically start producing acorns at 40 years old, peak in productivity at 80-120, can be productive for over 300 years, then rest for 300 years before moving to the next phase in their life cycle. But the rowan starts producing at just around 15, and will reach the end of its life within around 120 years.

After its productive life stage, a tree will become an ancient, then eventually begin to decay in the final stages of its life.

What Is A Deciduous Tree?

A deciduous tree is a tree that loses its leaves over the winter months. These trees shed their leaves each autumn. In deciduous trees, a complex range of physiological signals and changes within the plant lead to the process of leaf drop, also known as abscission. Deciduous trees lose their leaves to conserve water or better survive winter conditions and pests.

As the autumn arrives, with shorter days and cooler nights, chlorophyll production (for photosynthesis) in deciduous trees decreases. Chlorophyll is what gives leaves their green pigment. When the levels of this in the leaves reduces, other pigments in the leaves become more apparent, giving yellow, brown, orange, red and purplish hues to the foliage. This is why, in areas where we have shorter days and cool nights, we can get such stunning, bright, autumnal displays.

What Are Evergreen Trees?

Evergreen trees are trees which keep their leaves all year round. This includes conifer species such as pine, juniper and yew, evergreen oaks, holly, etc.. Typically, the leaves on an evergreen are thicker than those on deciduous species, and generally have a larger fraction of total plant biomass present as leaves, but a lower rate of photosynthesis.

Does Ivy Kill Trees?

If you see ivy climbing a tree, you may well be worried for the health of the tree. But the truth is that ivy will rarely do much damage to a healthy tree, and the benefits of having the ivy can outweigh the negatives.

Ivy is not a parasitic plant. It is not feeding off the tree in any way. It is simply clinging to the tree and using it as a support. While the ivy’s roots, in the soil below, will compete with the tree’s roots to a degree, this will not usually be an issue for a mature specimen.

The ivy attaches itself to the tree firmly, but this does not usually damage the tree substantially. If the ivy forms massive growth and excludes light from the leaves of the tree, then this could cause an issue – reducing the trees ability to photosynthesise, though not usually killing it.

If a tree is healthy and vigorous, however, it can usually co-exist perfectly happily with the ivy that is climbing it and it is not something to worry about.

If ivy does appear to be damaging a tree, then it is likely that the tree was already vulnerable, and was already aged, dying, diseased or rotten before the ivy arrived. If a tree is already weakened, ivy cladding can worsen rot, and make make the tree top heavy and more likely to tip over in strong winds.

Ivy is not a villain in the garden. Though in certain situations it definitely has to be kept in check, the benefits of having ivy around definitely outweigh the negatives. Ivy is very important for wildlife, and provides essential habitat, shelter and food – especially during the winter months.

How Can You Stop A Tree From Growing?

You cannot really stop a tree from growing, unless you want to get rid of it altogether. But you can restrict a tree at a certain height by undertaking pruning each year. This is not a one-and-done type thing, however. It is something that you will need to repeat annually (or even more frequently) to keep the tree at the size you require.

Remember, it is always best to think about the final size the vigour and growth rate of a tree when choosing one in the first place. If you want a lower maintenance garden, then you should mostly choose options that will suit the space when fully mature. Pruning a standard tree to keep it in check is generally a lot easier than more intensive pruning for neat hedges, bonsai etc…

Many trees are best pruned during the dormant period, when the pruning won’t spur on a lot of new growth. However, there are exceptions, and different trees are pruned at different times of year. So make sure you check the pruning guidelines for the tree or trees you have chosen.

When Is The Best Time To Plant A Tree?

The best time to plant a tree is between October and March, during the dormant period. It is best to choose a sunny, and calm day, for your own sake as the gardener, but also to increase chances that the tree will thrive. Avoid times when the ground is frozen or waterlogged, of course. And try to make sure that there is no extreme weather expected in the immediate future.

Planting in the autumn or early winter means that the roots will be able to get off to a good head start before shoots appear in spring. But less hardy trees may benefit from being planted in early spring, when better weather is just around the corner.

While these are the best times to plant a tree, it is generally best to plant out a tree as soon as possible after it arrives or you bring it home.

Which Are the Best Trees For a Small Garden?

If you have a small garden, you will often need to be careful about which trees you choose as specimen trees. Fortunately, there are plenty of options even for smaller spaces. Here are some trees for small gardens that you might like to consider:

  • Acers
  • Amelanchier
  • Apples (on dwarfing or semi-dwarfing rootstock) or other patio fruit trees.
  • Cercis
  • Cherry (ornamental types for blossom as well as fruiting kinds.)
  • Hawthorn
  • Hazel (especially corkscrew hazel with its twisted form.)
  • Magnolia
  • Rowan
  • Silver birch

Of course, these are just some of the many options that you could consider.

Can You Cut Down A Tree In Your Garden?

While of course it is better to plant trees than to cut them down, sometimes, a tree may sadly need to be removed. A tree might be damaging your property, or might be at risk of falling and doing damage. Try to avoid cutting trees down if you can. It can have impacts that are not always obvious to the landscape, soil, wildlife and people nearby. Consider taking other measures such as pruning or pollarding before deciding that the entire tree has to go.

Remember, losing trees can cause flooding or waterlogging issues, and all sorts of other environmental problems that you might not have anticipated. It might reduce the function and utility of your garden. And even reduce the property value of your home.

If the tree absolutely must go, you may legally cut it down as long as it is not the subject of a tree preservation order (TPO). A tree preservation order is a written order created by a local planning authority. It is designed to preserve trees that are of amenity value to the public. If a tree is protected by a TPO then it is illegal to cut it down, or to damage it in any way without the written consent of the local authority. If the tree in your garden can be seen from the road or pavement, it could potentially have one of these orders placed on it.

If you live in a conservation area, the trees in your garden may not have TPOs placed upon them, but are still subject to the same rules.

Note also that it is illegal to fell trees during breeding season as this could destroy nests.

How Can You Find Out If A Tree Has A TPO?

To find out if a tree has a TPO on it, contact the tree officer for your local council. They will be able to aid you in working out what to do about the tree in question.

Remember, however, that even when a tree does not have a preservation order on it, it will often be best to keep it standing if at all possible.

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