If you didn’t divide your spreading perennials last fall, you might want to make that an early task this spring. Just letting them go may result in their squeezing out other plants that share the same bed. If your spreading perennials are near a sidewalk, they may impede you or guests using the walk. If the bed is next to the lawn, these spreading plants may overflow the bed and kill the grass. Dividing is the method used to keep these spreaders in check. It’s also an inexpensive propagation method.
you’ve never divided perennials, it’s an easy DIY job. Just dig up the whole plant and lay it on a tarp. Then cut the root in half from the foliage to the bottom of the root. Finally, cut each section in half again, so that you’ve quartered it. The cutting method depends on the thickness of the roots and your strength. While many of our landscape professionals can cut sizeable roots with one blow from their sharp shovel, you may be more comfortable using a pruning saw or loppers. Your tool choice depends on the size of the job.
Once cut, return one quarter to the original planting hole. Backfill just as you would when planting a new plant. Finish by thoroughly watering it in.
What you do with the other three sections is up to you. I suggest you plant them in other beds on your property, give them to friends or contribute them to a charity plant sale.
Dividing perennials has a similar effect on them as pruning has on trees and woody shrubs. It makes them grow stronger and healthier.
If you’d rather not divide your own perennials, our landscape professionals will be happy to do it for you. And, the next time you buy perennials, check the nursery tags and ask one of the garden center horticulturists about their behavior pattern and if the plants you’re considering need dividing.
I prefer to do it in autumn, but that is only because I grow things. Division in autumn is more efficient and less work for most perennials that we grow. Now that I am taking care of some of the same sorts of plants in a landscape, I find that I prefer to wait for them to finish blooming. It is a bit more work, and the new plants must be watered more carefully but the bloom is much better of course.