Dividing perennials is one of those simple, satisfying gardening jobs that pays back in spades. Not only does it rejuvenate tired plants and boost flower production, but it’s also a great way to multiply your favourites for free.
If your border is looking a little lacklustre or you’ve got perennials that are too big for their boots, it’s time to get the spade out.
🌿 What Are Perennials?
Perennials are plants that live for more than two years, coming back year after year. Think hardy geraniums, daylilies, hostas, phlox, asters, and more. Over time, many form large clumps that become congested, leading to fewer flowers and bare patches in the centre. Dividing helps refresh the plant and encourage stronger growth.
📅 When to Divide Perennials
- Spring (March–May): Ideal for summer- and autumn-flowering perennials. The soil is warming up, and plants are putting on fresh growth.
- Autumn (September–October): Best for spring- and early-summer bloomers, giving them time to settle before winter.
Rule of thumb: divide plants opposite their flowering season — spring division for autumn flowers and vice versa.
🧤 Tools You’ll Need
- A garden fork or spade
- A hand trowel (for more delicate divisions)
- A sharp knife or pruning saw (for stubborn roots)
- Compost or organic matter
- A watering can or hose
✂️ How to Divide Perennials – Step-by-Step
- Lift the Plant
Dig around the clump with a fork or spade, trying to keep as much of the root ball intact as possible. Lift it gently from the ground. - Shake Off Excess Soil
This makes it easier to see what you’re working with. You’ll often spot the telltale signs of congestion: dense roots and little growth in the middle. - Divide the Clump
- For loose-rooted plants (like rudbeckia or astrantia), gently tease apart sections by hand.
- For tougher roots (like hostas or daylilies), slice through with a knife or saw. Each division should have a healthy set of roots and at least one strong shoot or bud.
- Replant Immediately
Improve the planting hole with compost or well-rotted manure. Water in well and keep the area moist while the new divisions settle in. - Aftercare
Mulch around the base to retain moisture and suppress weeds. Keep an eye out for slugs, particularly around soft new growth.
✅ Which Perennials Can Be Divided?
Here are some of the most common and reliable perennials that benefit from regular division:
| Divide in Spring | Divide in Autumn |
|---|---|
| Rudbeckia (Black-eyed Susan) | Hellebores |
| Echinacea (Coneflower) | Iris (after flowering) |
| Daylilies (Hemerocallis) | Hardy Geraniums |
| Sedum (Hylotelephium) | Pulmonaria (Lungwort) |
| Aster (Symphyotrichum) | Brunnera (False Forget-me-not) |
| Coreopsis | Bergenia (Elephant’s Ears) |
| Monarda (Bee Balm) | Japanese Anemones |
| Agapanthus (deciduous types) | Crocosmia |
| Penstemon | Geum |
| Veronica (Speedwell) | Tiarella (Foamflower) |
| Campanula (Bellflower) | Primula |
| Achillea (Yarrow) | Dicentra (Bleeding Heart) |
| Helenium | Epimedium |
| Phlox paniculata | Lamium (Dead Nettle) |
| Alchemilla mollis (Lady’s Mantle) | Astrantia |
| Nepeta (Catmint) | Viola odorata (Sweet Violet) |
| Shasta Daisy (Leucanthemum) | Saxifraga |
| Heuchera (Coral Bells)* | Heucherella |
*Note: Heucheras can technically be divided in either season, but spring is often better for recovery.
⚠️ Not all perennials like to be divided. Avoid disturbing peonies, oriental poppies, or woody-based perennials like lavender and rosemary, which may sulk or fail to regrow.
🌼 Final Thoughts
Dividing perennials isn’t just about tidying up – it’s an act of renewal. Plants benefit from more space and nutrients, and your borders get a lift in colour and vigour. Plus, you end up with free plants to share, swap, or fill out the rest of your garden.
So next time you see a big, bulging clump of greenery, don’t see trouble — see opportunity.
