As a garden matures, some perennial plants (plants that return each year) will benefit from being divided. This work may not be necessary every year, but keeping an eye on your garden will help you determine when or if a plant should be divided.
Why You Should Divide Your Plants
Rejuvenate
A previously healthy plant could benefit from being split if it’s now struggling with smaller flowers, weak stems and discoloured leaves, or if it is developing bald spots in its middle. Over time, as the plant spreads out, it will begin competing for nutrients and its older centre stems start to die. By reducing the number of stems, removing any dead individuals and replacing them with the healthier outer plants, you can keep your patch looking its best.
Reduce
If a plant clump is getting too wide, too dense or encroaching on other plants, divide the plant to reduce its number of stems. This is a great way to keep your garden tidy while also increasing airflow through your garden and reducing the risk of diseases like powdery mildew.
Expand
If you decide to divide a plant to rejuvenate it or to reduce its size, you will likely be left with some extra healthy plants. This is a great excuse to expand a garden without having to spend any money.
If sharing the plants with family, friends or neighbours, reduce the chance of spreading invasive species like jumping worms, by washing the roots and placing in a pot with clean potting soil, putting them in water as cuttings, or rinsing and replanting as soon as possible.