We become attached to our perennials and eagerly anticipate their arrival each year. So the concept of slicing them in two is disturbing. However there are many beneficial reasons to divide the perennials in your garden. Many plants actually need thinning occasionally so their roots don t become too crowded. Centres of old plants may die out or become woody and bare.
Division is also a way to get more plants for new beds, to swap or to give away.
Furthermore many perennials don t come true from seed, so you have to produce new individuals by the process of division. Also you may even have raised a seeding of your own that is distinctive enough that you want to propagate and spread it amongst your gardening friends. Dividing your perennials usually falls into two categories. Divide spring bloomers in fall and fall bloomers in the spring. Occasionally divide spring or summer bloomers right after flowering to give them part of a growing season to get re-established.