A bout the time my brother and his family visited a couple of summers ago, I discovered I had a dilemma. Yet I couldn't bear to just yank it all out. There are other good reasons to divide perennials besides clearing out your garden. Many plants actually need thinning occasionally so their roots don't get too crowded. Centers 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.
Because perennials often don't come true from seed, you have to produce new individuals by division. You may even have raised a seedling of your own that is distinctive enough that you want to propagate ones just like it. In This Article 1. Dividing Fibrous Roots 3. Dividing Offsets 4.