Perennial gardens are a beautiful additions to any yards or home perimeters. They do require some maintenance to keep your gardens looking beautiful. As perennials grow, they expand and sometimes attempt to crowd out their neighboring perennial friends. You can choose to divide them out by cutting into their roots and removing part of the plant or you can just trim down some of the branches on the sides to allow a definition between plants and increase circulation. Doing this will increase the beauty of your gardens and keep a nice textured appearance to your gardens. You will find out quickly what plants you can divide and which one you cannot. If dividing, you are cutting into the root system. You will need to cut of many of the leaves as the plant usually is unable to support the top leaf growth. The plant will usually regenerate new leaves within a few weeks when the plant has recovered from the shock.
There are many many plants that do well with root divisions. At a later post I will give some tips on which plants do better than others. The list could be exhaustive and for most gardeners the trial and error approach works best. It may be simpler to cutting off side branches that crowd out other plants.