Perennials can be a wonderful addition to your landscape. As they mature and grow however, plants may benefit from being divided every few years. There are many reasons to divide your perennials but the main reason may be to help control the size of the plant, to add more of the same plant to other areas of your landscape without the expense of buying plants, or to just keep the perennial from spreading beyond its allotted space. Dividing your perennials is an easy project that requires little time and will help keep your garden fresh and neat for the upcoming years.
Different perennials may require division at different times of the year. In general however, spring and summer blooming perennials are best divided in the fall while fall blooming perennials recover better if divided in the spring. Plants such as hosta, daylilies and coneflower all benefit from being divided in the fall. Perennials such as asters and sedum should be divided in the spring as they mature to conserve space.
If your plant seems to have voids in the middle of the clump or if it appears like there are less flowers than normal you should divide your plants. In general, your plants may need divided every three to five years. If your plants are five years old, flowering great and not overgrowing their space, division may not be needed. When you do decide to divide your plant, ideal conditions are on a cloudy day with cool, wet weather in the forecast. Hot sunny days will quickly dry out the leaves of your plants and may over stress the plant beyond repair.
To divide your plant, use a sharp spade or shovel and make sharp downward cuts around the drip line of the perennial. This is generally six to twelve inches around the base of the plant as to disturb as little of the root system as possible. Once you have dug around each side of the plant use your shovel to pop the perennial out of place. Shake off excess dirt to loosen the root system and remove any dead stems or leaves. Using a sharp knife or shovel, separate the desired roots from the parent plant and place the divided plants in their new home. 
