Are you a sucker for trees?

Why do suckers form?

Several factors can contribute to the formation of suckers. Here are some of the most common causes:

Root Damage or Pruning: A rootstock gives off suckers as a form of defence against damage, to protect itself. On the nursery after we stock top our field crop in the early spring, the rootstock throws off numerous suckers to try and rejuvenates itself. On more established trees suckers can form naturally or due to root damage e.g. if a lawn mower blades strikes a root, then it is likely that suckers will form from the wound.

Trees under stress: You may also see suckers forming if an established tree is under stress conditions, this again relates to the tree attempting to protect itself. This may be in very wet conditions where the root system is struggling due to waterlogging, or the other extreme of very dry conditions where the roots are drying and the trees is doing everything it can to survive.

Genetic Predisposition: Some species of trees and rootstocks are naturally more prone to sucker growth than others. For instance, fruit trees like apples and cherries are well-known for producing suckers, particularly if their rootstocks (often used to control tree size) are stressed or damaged.

How to Manage Tree Suckers

While tree suckers are common, they can usually be managed with a bit of care and attention. Here are some strategies for dealing with them:

Pruning: The most effective way to manage suckers is through regular pruning. Suckers should be cut back as soon as they appear. On juvenile trees, this can be done with a sharp knife but on more established trees secateurs would be the preferable tool and where possible avoid suckering before rain is forecast, any cuts to a tree expose the tree to infection and this is more prevalent during wet conditions. Ideally this should be undertaken during dormancy. Cut the shoots close to their base. Regularly removing them prevents the tree from diverting too many resources into sucker growth.

Avoid Wounding the Tree: Since pruning and root damage are common causes of sucker growth, take extra care to avoid injuring your tree. Ensure that any cuts made on the tree are clean and made at the appropriate time of year (usually during dormancy). Also, avoid damaging the tree’s roots whenever possible.

Improve Tree Health: Ensuring that the tree receives proper care can help reduce stress and the likelihood of sucker growth. This includes adequate watering, fertilisation, and protection from pests and diseases. Healthy trees are less likely to produce suckers in response to stress.

Mulching and Soil Care: A layer of mulch around the base of the tree can help maintain consistent soil moisture and temperature. Make sure to mulch properly, avoiding excessive mulch at the base of the tree. Additionally, improving drainage around the tree’s root system can prevent stress-related sucker growth.