Why do my shrubs look like this? Shearing Decline

“Why do I have bare spots appearing in my shrubs? They have been fine for years and now something is wrong with them.” This is something that we hear frequently from homeowners who fear there is some disease or insect invading their otherwise healthy shrubs. Often this is a direct result of age decline in shrubs brought about by excessive shearing.

A common misconception as well as poor cultural practice in landscape maintenance, is that shrubs need to be kept in a tight hedge or ball shape to look ‘neat’ and to keep them at a certain size. This causes issues on several levels. When you shear a plant, you are removing the newest leaves. This is where the most photosynthesis occurs in a plant to create food. When you remove these and leave only the older, hardened leaves, plants cannot produce enough food to thrive. This lack of adequate food makes them weak so that they are susceptible to more issues like fungal diseases.

Shearing also stimulates leaf production causing the shrub to have very dense leaves at the end of the branches where new growth occurs. When the ends of the branches are this thick with leaves, the interior starts dropping leaves due to lack of light. Over time you will have a kind of a ‘shell’ of leaves on the outside of plant with no leaves on the inside. This shell will also trap moisture and obstruct airflow that can lead to fungal infections.

Once the shrubs get into this state there isn’t really anything that can be done to help them. Over time with all these issues occurring the plant will just get weaker and weaker. It will start to decline in health with limbs dying leaving gaping holes in the shrub. The shrub will eventually just fall apart. Plants that are sheared just have a much shorter life span than those that are left to grow naturally or have minimal pruning done to them.

Best cultural practices for shrubs start with proper planning during the landscape design process. Choosing the right plants for the right application is key. Don’t install plants that grow naturally to 8’ tall under a window where they must be kept at 3’ tall. Once established, let the plants grow naturally if you can. If you must trim them, do so by pruning instead of shearing. Pruning means you are selectively removing branches to maintain the health and size of the shrub versus removing all outer edges of the shrub with mechanical hedge trimmers. This is often a more time-consuming (and expensive) approach, but it is better long term for your plant’s health and aesthetic. Annual fertilizing and proper watering practices will help keep your shrubs strong and around much longer.



This article written by Shelly Ryan