How To Grow Trees In Containers
No garden to grow a tree? No problem, just grown in a large container
Here at Hayes Garden World we are often asked if you can grow trees in containers. The answer is yes you can, provided you take a few things into consideration, such as; size, interest, amount of care you can give the tree and position. The size of the pot relative to the tree you wish to grow must be taken into consideration, also the type of compost used. A disadvantage of growing trees in containers is that they are high maintenance and very often not as long lived as they would be planted in the ground. A mature tree consumes an enormous amount of water in the summer, so you may have to soak it morning and evening or else set up an automatic watering system, such as from Hozelock. One of the advantages of growing trees in containers is that if your wish is for a Mediterranean or tropical garden you can have one, provided that you have either somewhere frost free to keep them in winter or the dedication required to wrap them up sufficiently well.
Choosing a Site to Place Your Tree
One of the first considerations is where do you want the tree to be situated. Do you want anything particular from the tree, such as, covering an unsightly garage wall, screening the view from the neighbours, winter colour, scent, food crop, food for birds or just a focal point. Is the selected spot windy? If so this rules out the gorgeous Japanese Acers and Bamboos as they do not like the wind. One of the Sorbus species would be a good choice here. Sorbus cashmiriana is a beautiful tree with white flowers, flushed pink, in spring followed by white berries in the autumn, which the birds will soon devour. In open ground the tree will reach 10 metres (30ft) but keeping it in a pot will keep it small.
A sheltered spot out of the wind and the midday sun would be ideal for the Japanese maples. They are beautiful trees for autumn colour and many of them are small & slow growing. Acer palmatum atropurpureum would be a good choice as the leaves are crimson – bronze in summer and turn brilliant scarlet in autumn, Bloodgood is one the most popular varieties. Sango-kaku (Sankaki) is another excellent variety as there is winter colour in the form of the new stems being bright orange - red. This variety also has good autumn colour in the form of soft yellow leaves.
Seaside gardens present a bit of a challenge owing to the salt laden winds which will burn the soft new growth of most trees. Sorbus aucuparia, discussed above, will tolerate the winds, as will most of the Salix (Willow), and Ilex (Holly) species. A couple of large shrubs, Griselinia and Laurus nobilis are good evergreen choices and in an open garden make a medium tree but are unlikely to become too large planted in a pot. If you can put up some screening from the wind then you have more choice with a lot of shrubs growing to a height which is below that of the screen, once it grows above the screen then you are faced with the same problems. There are several options for screening stocked in the garden centre, from the traditional lapped panels, from Forest, to rolls of willow and split cane.
Cold exposed areas face the problem of strong winds and cold winters therefore the plants grown here must be very hardy and have strong enough leaves not to suffer from wind burn. The choices for containers are limited but Crataegus monogyna (Hawthorn), Ilex (Holly), Juniperus (Juniper) and Sorbus (Rowan) are all good options. A selection of these trees would provide you with spring flowers; Hawthorn and Rowan, berries for birds; Hawthorn, Holly and Rowan, autumn colour; Rowan, and for evergreens there are the Holly and Juniper.
If the site is sunny and sheltered then the world is your oyster, almost, there is a huge choice available.
What plant do I choose for my pot?
Plant soil and nutrient requirements are different but growing in containers means that you can provide exactly what the plant requires. If you live in an area which has a lime soil, which would not be suitable for the acid loving Azaleas, Camellias and Rhododendrons, then you can grow them in containers with ericaceous compost.
One of the easiest group of trees to grow in containers are conifers; they require very little feeding, seldom require pruning and you will have greenery all the year round. On the down side they don’t flower and don’t give any autumn colour. They seldom suffer from pests and diseases but will suffer from wind burn if in a windy position and if placed next to a wall must be turned regularly otherwise the side facing the wall will go brown. Make sure you choose a tree appropriate for your container and avoid the fast growing species such as Cupressocyparis leylandii, the dreaded Leylandii. As a general rule if a conifer grows fast it doesn’t stop until it reaches a considerable height.
What sort of container do I need for my tree?
Most garden centres now stock a large range of containers priced from a few pounds to several thousand. You must make sure that the container is large enough to accommodate a tree but not too large that the tree will be sitting in a lot of waterlogged compost over the winter. There are several grades of terracotta pots but generally the more expensive they are the more resistant they are to frost. There are now a lot of good plastic and fibre clay pots on the market which are more resistant to frost than the terracotta.
What compost do I use?
When you plant the tree put plenty of broken crocks in the bottom, this aids drainage and stops the holes blocking with silt. If possible spend a few extra pounds on a loam based compost as it will drain better than a peat based one and won’t hold the water in winter. Using a peat based compost will increase the chances of a terracotta pot splitting with the frost as it retains water then expands when it freezes, you will probably also loose the tree if it stands in water over the winter. Most trees can stand the frost but not when their roots are waterlogged.
I know that this sounds like a minefield but if you want any help there are experienced nursery staff who are happy to recommend a tree to plant in your chosen container and site.