PROPAGATING PERENNIALS FROM DIVISION
There are several ways to propagate by division depending on the type of plant, and of course the number of extra plants you need. The simplest is the clump forming, used for plants such as the Perennial Geranium, the Aster or the Astrantia (one of my favourite plants, incidentally).
To begin with lift the plant with a spade, i.e. dig it up, and include the entire root zone, if possible. The best time to do this is when the new shoots are about 2 ins (5 cm) long – this is most likely in the spring. If the clump is large, divide it in two with your spade, then tease out the small pieces by hand. Each of these should have about half a dozen new shoots and lots of nice, fibrous roots. Remove the old dead stuff from the centre of the plant and throw on to the compost heap.
Replant the divisions immediately either in pots for growing on, or in their final growing spot, ensuring that you plant them at the same level in the soil as they were originally.
If you have found the root ball very dense, tangled and generally impenetrable, then use the ‘two-fork’ technique. This involves using two large digging forks, back to back, placed in the centre of the plant. Then, using a firm but careful action, lever the clump apart. You should then be able to divide further by hand. Tough rooted plants, such as Hostas, can be washed clean of soil and the selected crowns separated with a sharp knife. It’s best to use a knife rather than a spade as there’s a risk of fungal problems. Next, dust the cuttings with sulphur, or other fungicide, and place each one in its own pot for growing on.
The final type of perennial division is ‘dividing rhizomatous perennials’ such as Bearded Irises. Once the Iris has finished flowering, lift the rhizome clump and shake off any surplus soil. Separate into sections by hand. Select nice young rhizomes with healthy roots and throw the old rhizomes on to the compost heap. Section the selected rhizomes into 2-4 ins (5-10 cm) lengths with a sharp knife. Trim the slender, fibrous roots by one third and either pot up or place in their final growing place. It’s also a good idea, if you’re planting straight out, to trim the leaves to a ‘mitre’ shape to about 6 ins (15 cm) long as this will reduce windrock.
Whilst you may not have room for all the extra plants you’ve now produced, they do make great and much appreciated Christmas and birthday presents!
by Helen Wand
The Organic Veg Doc