Perennial plants will always be popular in the garden because they require so little care. Sooner or later, however, many perennials will get “too big for their britches” and will need to be divided.
How will you know when a perennial plant needs to be divided? Some may need to be divided every 3-4 years, others will quite happily grow for up to ten years before they need to be divided, and a few species don’t like to be divided at all. The best thing to do is to let the plants tell you when it’s time. Divide a perennial when you notice any of the following symptoms:
- The plant is flowering less than usual, and the blooms are smaller.
- Growth in the center of the plant is dying, leaving a hole in the center with growth only around the edges.
- The plant isn’t growing as vigorously as it has in the past.
- The plant has outgrown its space and is becoming crowded by its neighbors.
Spring is the best time to divide most perennials, although there are some exceptions to the rule. Perennials that bloom in the spring, such as iris and poppies, can be divided in late summer to early fall. Some plants don’t like to be divided or moved at all. These homebodies include peonies and tree peonies, foxtail lilies, bleeding hearts, goatsbeard and butterfly milkweed. They should be divided only when absolutely necessary. Never divide a perennial while it is blooming as this would be too stressful for the plant.
The first time you divide a perennial, you’re going to be nervous about it. That’s natural this process makes every gardener nervous at first. But the more you divide perennials, the easier it will become. Dividing perennials is often more stressful for the gardener than for the plants.
Follow these simple steps to divide your perennials:
- Start by digging around the perimeter of the plant with a sharp spade.
- After digging all around the plant, slide your spade beneath the clump and lift it out of the ground.
- Use a sharp spade or a knife to cut the clump into smaller, more manageable plants.
- Discard any sections of the plant that are dead and trim off any damaged roots.
- Keep the divisions moist and in the shade until they can be replanted.
- Replant the divisions at the same depth the plant was originally growing.
- Water the newly planted divisions well and keep them from drying out while they re-establish themselves.