Why Dividing Perennials Is Good For Your Plants AND Your Budget
Discover why dividing perennials matters, how to do it and which plants are easiest to divide.
Only in gardening does division turn into multiplication. We’re talking about dividing plants—digging up clumps of crowded perennials and splitting them into smaller individual plants.
Why You Should Divide Perennials
“Dividing perennials gives you more plants to place in your landscape or to share and swap with friends and neighbors,” says Justin Hancock, horticultural craftsman for Monrovia Nurseries.
Of course, that’s not the only benefit of dividing plants. “The biggest value in dividing perennials is that it keeps most plants healthy and looking their best,” Justin says. While not all perennials and grasses need to be divided, the process can help reinvigorate them and encourage them to produce more blooms.
When to Divide Perennials
It’s usually plain to see when they’re ready for a breakup. “The most obvious sign that your plant could use dividing is when you see it start to die in the middle—as it grows, it is literally crowding itself out,” Justin explains. “Other signs may be a decrease in flowering and overall performance. And the clump may be quite large.” Make sure you’re not making these other common mistakes with perennials.
Some plants can be split anytime, such as daylilies, but the best season to divide spring or summer blooming perennials is in fall, at least a month before the ground freezes. Wait until spring to divide anything the blooms in autumn. Learn what other garden chores you should be doing in fall.
How to Divide Perennials
Dig up the plant you’re splitting with a spade or fork on a cool, cloudy day. Lift the plant to remove any loose soil and to tease the roots apart. And separate the plant into smaller divisions, making sure each piece has growing shoots and roots.
For perennials with finer root systems are among the easiest to divide. Plants like yarrow, aster, coreopsis, monarda and sedum are simple enough to split with a spade. Larger ornamental grasses are more tricky. “The bigger or deeper the root system, the more challenging the physical act of dividing can be,” Justin says.
Pull small plants apart by hand, slice medium-sized plants with a sharp spade or serrated knife, and split large root clumps with two spades. Here are some of our favorite garden tools.
To lessen the stress on the plant, Justin recommends digging holes for the daughter divisions before digging up the mother plant. “That can greatly reduce the amount of time your plant is out of the soil with its roots exposed,” he says. Justin also advises trimming plants to compensate for lost roots. “Roots absorb moisture for the plants, and leaves release moisture as they breathe,” he says. Cut back the foliage to reduce the burden for the roots and to help your new plants establish.
Replant immediately and water thoroughly. Here’s more tips for dividing perennials.
Perennial Plants That Are Easy to Divide
- Siberian Iris