Dividing perennials is an essential part of the maintenance of a garden. Plants work as hard as they can to grow as large as they can, and in ornamental gardens we give them every advantage. This means that the roots in the center of a perennial can become so densely overgrown and tangled that they simply strangle themselves to death. It’s the same concept as a plant being root bound in a pot. So, just as you would cut the roots of a root bound plant, dividing the plant prevents this from happening. It’s also why plants are supposed to be planted a certain distance apart.
What perennials need dividing? Iris (the irises in the photo above are in desperate need of this) sedums, daylilies, lambs ear, Shasta daisies, and bee balm are just a few of the many perennials that might need divided. But just about any perennial that has gotten overly full or has spread beyond its designated area can and should be divided.
Dividing plants is very easy, but can be nerve wracking. Before you even touch a shovel, you need to prepare a place for the plants that you dig up. While you’re working on them, the plants should be somewhere shady, cool, and preferably damp. This keeps the plant from getting too stressed. A wet tarp laid out under some trees or a bucket full of damp newspaper in the garage are both good ways to store them. If the roots dry out too much, let them soak in a bucket of water for an hour.
Also don’t shake the dirt off the plants as you dig them up, the more dirt around the roots, the less likely it is that the plant will dry out.
Next you have to dig up the plant. If it’s small enough, just take the entire thing out, as shown with the hosta picture above. Once out of the ground, you’ll want to find a natural divide in the plant’s foliage. It won’t be a straight line or directly down the middle, but nine times out of ten you’ll be able to spot a good dividing point. A shovel is usually the easiest way to make the cut, slicing the plant in one swift movement. But if the root ball isn’t thick or if your not sure of your shovel skills, a pair of hand pruners work just as well.
If the plant is too large to pull out all at once, you’ll have to divide it as you dig. Start at the root line and loosen around the plant. Then look for those natural divides. Don’t be afraid to use a shovel for plants this large, if they’ve lasted this long it’s because they have strong, healthy roots. Cut them into small chunks, about the size of a one gallon or three gallon pot, and pull them out as they’re cut.
Now you have the wonderful problem of finding homes for all your new plants. Plant them as soon as possible and water generously. Fertilizer can also help the plants settle into their new homes. If you don’t have a place to plant them that day, break out some old pots and store them that way. Divided plants also make a great gift for friends and fellow plant enthusiasts.
The best part about perennial plants is seeing them grow and thrive year after year. Dividing them every few years gives you more plants for free and helps your plants stay healthy and vibrant for years to come.
