DIVIDE HERBACEOUS PERENNIALS
Give your borders a facelift and make some new plants for free at the same time
Herbaceous perennials can become less productive over time. The best way to remedy this and keep them at their floriferous best is to divide them. How often you’ll need to do this varies from plant to plant but a good rule of thumb is every three to five years, when the centre of the plant looks woody and congested. Division is also a great opportunity to make more plants to put elsewhere in the garden or to give away to friends. Not all perennials can be divided. Those that make crowns of foliage with fibrous roots, such as hardy geraniums, astrantias and primulas, are happy being split, but those with one main taproot, such as members of the thistle family, are best left. Spring and early-flowering plants can be divided now and they’ll establish quickly in the warm, damp soil. Late-flowering plants such as rudbeckias, heleniums and grasses are best divided in late spring.
How to do it
Lift the plant Dig around the rootball and carefully lift it from the ground. Place it on an old compost bag or on a sheet of plastic. Divide the clump For large clumps, push two garden forks into the centre of the plant, back to back, so they’re touching. Pull the handles together to lever the plant apart. Keep doing this until you have lots of smaller sections. Discard the centre of the plant. Divide smaller clumps by hand, pulling the plants into pieces. For really tough plants you may need a sharp bread knife or even a saw to cut through congested roots. Replant the pieces Plant the smaller sections in holes enriched with well-rotted garden compost. Avoid bending roots to fit in the hole and instead trim them. Backfill with soil and compost, then firm in well. Water with a full can of water for each plant. The plants will grow away quickly in spring.