Garden care: When and how to divide perennials

This article discusses how to make more plants by dividing them.

You’ve probably heard people talking about dividing their plants. What does that mean and why on earth would they do that to the poor things? Well, actually, it is usually done for the health of the plants. These perennials will need to be divided to keep them from overcrowding or dying out in the center. Sometimes, a plant that is too vigorous also will need to be divided to keep it from taking over the garden. To divide perennials, you literally cut, chop, or pull the plants apart to make several more plants. You will have several new plants to put in another bed or trade with other gardeners, and they will become more vigorous and healthy after they are divided and replanted.

How do you tell which perennials need to be divided? First, look at your plants. If they come from a single stem, you cannot divide them. They should have many stems coming from the same plant. Some plants that grow quickly and need dividing frequently, at least every three years, are Hosta, Lirope, Sedum, Monarda, Lily of the Valley and Purple Coneflowers. Other plants, such as Peonies, may not need to be divided for four or five years.

Garden care: When and how to divide perennials

When you are thinking about dividing your plants, you should consider the season. If the plant is a spring blooming perennial, you should divide it in the fall. A fall blooming plant should be divided in the spring. However, you can also usually divide plants as soon as they are done blooming if you use extra care and baby them a bit.
When you divide Perennials, you will need a shovel, a sharp knife, and a hose. If they are too overgrown and very tough to divide, you may even need two pitchforks and a small tree saw. (Some very vigorous grasses are very hard to divide if you let them go for several years.)

Many plants can just have their roots untangled to be divided. Perennials this works well for are Lamb’s Ears, Geranium, and Daylilies. Dig up the entire perennial clump and wash off the dirt so that you can see the roots. Gentle untangle the roots or tubers from each other. If the plants have tough tubers, such as those on Peony or Solomon’s Seal plants, you may need to actually cut them apart. Make sure there is at least one, preferably two, eyes on each tuber piece you cut off. Make sure the cuts are sharp and clean to avoid disease and rot on the cut tubers.

What if you can’t get the plant to divide? If you have a very tough Lirope or grass, you may need to use a different method. Dig up the plant and turn it over and wash it off. Place your pitchforks in the center of the plant and pry the plant apart by pulling the forks away from each other. If the clump is still too big, pry it apart again.

When you divide any plant with big leaves, you may have to cut back some of the foliage to encourage root growth. Keep the plants well watered the first few days so they can reestablish themselves.

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