Depending on the shade amd soil conditions many plants can be grown under trees
Depending on the shade amd soil conditions many plants can be grown under trees

This week’s question is one that affects many gardens- the impact of trees on other planting. Jenny Bough from Gateshead asks;

‘Part of my garden is in shade for most of the day because of trees in a neighbour’s garden. Since I cannot remove the trees, what can I do to improve the conditions for my plants? And what plants will grow well?’

If the trees grow close to your garden the shade will probably be dense, and the soil may well be permanently moist from overhead drip. If so, you can improve the drainage by adding coarse grit to the soil under the tree and plant moisture- and shade- loving plants such as hardy Ferns, Primula species, Violets and Periwinkles. If you have lighter or more dappled shade then there are plants which like these conditions: Lilies, hostas, Azaleas, Rhododendrons and Blue Poppy (Mecanopsis) for example.

Epimedium- a good choice for dry shade
Epimedium- a good choice for dry shade

If the tree is close to your boundary, or indeed within your garden, and its roots make the immediate area very dry and shady, then plants such as dwarf Cyclamen (C. hederifolium), small-leaved Ivies and Epimedium should do well. You could also try to dig out a few pockets where bulbs can be planted. If you can mix plenty of compost or other organic matter  into the soil then many more options are open to you as the soil will be relatively nutritious and will retain moisture better. The London Orchard Project have added a helpful piece of advice:

‘Wait until the tree has established before any underplanting is carried out. Then be sure to plant perennials,  as (these), including trees, prefer a fungally dominated soil, whereas annuals prefer bacterial domination. Also, disturbing the shallow feeder roots of the tree can be minimised by not having to replant/remove annuals.’

Some trees produce roots close to or above the soil surface, which then send up new shoots or ‘suckers’; e.g Poplars. If you want to grow grass over these root runs, once again the best approach is to ensure a good depth of topsoil above the roots and so give the grass a good layer of soil to grow on and reduce the chances of suckers appearing. Another approach- and one I’ve used in Old School Garden under a large Black Poplar tree- is to cover the immediate surrounds of the tree with landscaping fabric and then use a decorative aggregate or other material as a covering (I’ve used purple slate). This has reduced, but not entirely removed the problem of suckers appearing. Alternatively, there’s nothing else for it but to keep pruning/mowing off the shoots as they come up. This is best done in early summer after the tree has put on its initial growth spurt- doing it in the dormant season will only encourage more suckers to appear in the new season.

Some trees (in this case a Maple) will send out shallow or surface level roots from which new shoots or 'suckers' will grow
Some trees (in this case a Maple) will send out shallow or surface level roots from which new shoots or ‘suckers’ will grow

Further information: a useful guide to tree care

Old School Gardener