What is a perennial?
Perennials, by definition, are plants that live more than two years. Some perennials, like peonies, live for decades, others like gaura, live 3-5 years. Ballon flowers or Platycodon grandiflorous, live 20 years or more without needing division. Each plant is different, and some, like black-eyed Susan, reseed everywhere in the garden, extending their lifespan for as long as you want.
Perennials are also loosely defined as anything that doesn’t have a woody structure, i.e., herbaceous perennials. Though, technically, trees and shrubs are perennials, too.
Why divide perennials?
Many beginning (and not-so-beginning) gardeners think of perennials as a one-and-done. Not so. Perennials provide years of beauty to our gardens but do require some maintenance. Division is a primary task associated with perennials. Why do we divide perennials?
Perennials can get too big for their space, crowding other plants.
Division helps with fungal diseases and pest control as it allows for better air and sunlight circulation.
The center of plants start to “bleed out,” forming a donut hole in the middle.
Perennials are producing fewer flowers, or straggly-looking leaves, or weak growth. (This could also be a sunlight issue.)
It’s a quick and easy way to grow the garden through propagation.
When is the best time to divide perennials?
Now is a good time to divide perennials as they die back. The soil temperatures are warmer than the air temperatures which encourages root growth–a good thing.
Rule of thumb: Divide spring-blooming perennials in fall. Divide late-summer, fall perennials in spring.
How to Divide Perennials: Example Shasta Daisy
For more information on a variety of perennial divisions, check out these sites.
Written by Cinthia Milner, garden coach, and blog writer.
BB Barns serves all of Western North Carolina, upstate South Carolina and Tennessee.