We see large trees growing in parks, botanical gardens and commercial spots. These trees provide beauty, shade and shelter for birds and other wildlife. In your average home lawn many large trees are not suitable as they grow too big. Your local nursery will be able to advise you on smaller more suitable trees to choose from.
Whether in a garden bed, in the lawn, large roots cause numerous problems, especially those at or near the surface. Casaurina, Evergreen Alder, Ficus and Liquidambar are a few examples of trees with extensive root systems but there are many more that can cause problems with your garden.
Suckering is the vegetative formation of a new stem and root system from an adventitious bud of a stem or root. This can occur either naturally or by human action. Such asexual reproduction is based on the ability of plants to regenerate tissues and parts. Suckering allows horticulturists and agriculturists to reproduce a desired plant over and over without significant intervention.
Suckering can be a real pain for lawns though – Robinias for example, will send up suckers from the root stock if the roots are damaged or disturbed, causing saplings to spring up all over the place. Mowing, whipper snipping and digging can actually cause this problem. The roots also sucker if they hit an obstacle. In an average size garden, it’s best to avoid this type of tree completely.
Whipper snipping close to tree trunks can easily lead to ring barking, which is the removal of bark around the base of the trunk. This can lead to the death of the tree, so you are advised to keep away from the trunk.
Trees and lawns will compete for water, nutrients and light. Thinning grass around the base of a tree is very common. Choosing a shade tolerant grass like Sir Walter DNA Certified will help with this but there are limits to how much shade any lawn grass will tolerate.
A lot of the time it is better to keep the lawn away from the base of the tree and spreading mulch instead. This reduces competition and eliminates the chance of Ring Barking when whipper snipping, or damaging surface roots when mowing.
Some varieties of buffalo lawn, such as Sir Walter DNA Certified, enable good grass coverage right to the tree base, even in heavy shade.
Keeping your lawn slightly longer in the shaded areas under trees will keep it in better shape especially in Winter. Never remove more than one-third of the leaf and leaving a few grass clippings won’t hurt either. Obviously, a well-chosen shade tolerant grass, like Sir Walter DNA Certified or Sir Grange, is always the best choice when considering trees.
When installing a new lawn try and avoid digging out important tree roots or adding soil over them. Extra soil will change the oxygen/carbon dioxide ratio around the roots, upsetting the delicate balance of these two important gases and lead to problems, including potentially the death of the tree which would be sad, and inconvenient!
If you have a special tree and are unsure what to do, call in an arborist for expert advice.