By Jennifer Langille
Perennials are the gift that keeps on giving. Not only do they return year after year, but many also multiply and improve with age – until they start to get a little too crowded. That’s where division comes in.
Dividing perennials is one of the easiest and most satisfying ways to rejuvenate a tired garden, keep plants healthy, and grow your garden for free.
1. Why Divide Perennials?
There are three main reasons:
- Health: Crowded perennials may bloom less or die out in the centre. Division brings back vigour.
- Space: Some perennials spread aggressively. Division helps control them.
- Sharing and expanding: Division lets you transplant extras elsewhere – or share with neighbours and friends.
2. When to Divide
The general rule:
Divide spring- and summer-flowering perennials in the fall, and fall-flowering perennials in the spring.
That said, you can divide most perennials in either season if you take care to water well and avoid extreme heat or cold. Here’s are a few common ones:
Spring Division:
- Asters
- Black-eyed Susans
- Coneflowers (Echinacea)
- Ornamental grasses
- Joe Pye weed
Fall Division:
- Daylilies (Hemerocallis)
- Bearded Iris
- Hostas
- Peonies (with care)
- Bee balm (Monarda)
Early spring and early fall are ideal—cool, moist conditions help new roots get established.
3. How to Divide Perennials
Step 1: Water the plant well the day before.
Moist soil is easier to work with and less stressful for the plant.
Step 2: Dig up the entire clump.
Use a garden fork or spade to loosen the soil around the plant. Gently lift the entire root ball from the ground.
Step 3: Separate the crown.
- For soft-rooted perennials like hostas or daylilies, gently pull them apart by hand, or slice through the crown with a sharp knife or spade.
- For tougher-rooted types like ornamental grasses, you might need two garden forks placed back-to-back—or even a handsaw.
Aim for divisions that have at least 2–3 healthy shoots and a good portion of roots.
Step 4: Replant promptly.
- Plant divisions at the same depth they were growing before.
- Water deeply after planting, and keep the soil moist while they re-establish.
- Trim back any floppy top growth to reduce transplant shock and help the roots focus on getting established.
4. What Not to Divide
Not all perennials appreciate being disturbed. These are best left untouched:
- Baptisia
- Bleeding heart (Dicentra)
- Poppies
- Lupines
- Peonies (can be divided, but only very carefully and rarely)
Always research a plant before dividing—if in doubt, start with the vigorous spreaders and leave the delicate or woody perennials alone.
5. Extra Tips for Success
- Don’t divide during drought or extreme heat.
- Add compost to the planting hole to give your divisions a boost.
- Label your divisions if you’re moving them elsewhere.
- Share your extras – it’s a great way to spread beauty.
- Label your divisions if you’re moving them – this saves confusion later.
Final Thought:
Dividing perennials isn’t just a maintenance chore – it’s a way to cultivate health, connection, and abundance in your garden. There’s something deeply satisfying about turning one happy plant into two, four, or even ten. It’s gardening magic that costs nothing but gives so much back.
May 2025