Propagation Workshop

Contributed by Editor

On October 13, 2019

A report by Jenny Gibb on a Plant Propagation Worshop held in September with Colin Moat.

More plants for free! Propagation has obvious appeal to Hardy Planters, but not everyone has the confidence or knowledge to try it. There was such a demand for this event that Colin Moat kindly agreed to do two sessions for his keen pupils. We met at Colin’s and had tea and biscuits on his terrace, watching dragonflies patrolling the pond, before driving to his polytunnel.

Colin uses a peat-free commercial planting medium prepared for him, a mix of composted bark and coir with additions including an anti-vine weevil mould and a supplementary granular feed. He uses this medium for all plants, including ericaceous and seedlings. It is also available to gardeners from Melcourt (without added mould or feed); it drains well but this washes out nutrients so adding granular feed such as Osmocote into the compost helps maintain feeding through the growing season.

He also uses vine weevil nematodes later in the season, especially at this time of year. Vine weevils love plants with thick roots (fuchsia, heuchera, primula) into which the larvae will burrow. A plant can still be successfully propagated after vine weevil attack, but you must examine it very carefully to check that the larvae are not still burrowed into the plant’s fleshy root or stem base.

Before we got hands-on, Colin demonstrated his division process. He has found that even long-standing HPS members can be nervous of actually splitting a cherished plant, so the chance to have a go with an expert watching was invaluable. Have a small, clean, sharp straight penknife or similar to hand, and a large bucket of clean water.

If the plant is very leafy, cut it back by about two-thirds; the resulting plantlet will have enough leaf for photosynthesis but not too much to dry out and overwhelm its small root system.

The basic method is to remove any dead leaves, weeds or algae from around the plant, and to dunk it in the bucket to wash off soil (and weed seeds, pests and other debris) from the root system. Then the key is patience – gradually tease apart the roots to expose the base of the plant, re-dunking and using the blunt back of the knife to push through the root ball as necessary. Discard any congested bits of old matted root, especially from the centre.

Many plants like hostas will have natural ‘fault-lines’ that can then be (more or less) gently levered apart by hand into separate pieces. Others like francoa will have a solid central stem base that can be halved or quartered with the knife. If in doubt, don’t divide too much; very small plantlets may not survive. Pot up each plantlet in a small 9cm pot (a touch of mulch will keep weeds down and moisture in), water it and label it.

We got stuck in with a hardy geranium, an astrantia and a francoa (whose mass of leaves resembled a cabbage before they were cut back so we could see what we were doing). A sedge (Carex comans) had a very dense root system and we watched as Colin took time and care to gradually work through the plant and separate it into at least six pieces, which we gratefully potted up. Our final victim was a low-growing tender pelargonium brought along by a member, where the leaves were left uncut.

We finished with a tour of the polytunnel, enthusing over some lovely varieties that Colin is bringing on. We look forward to his next sales table! Many thanks to Paul Ingleton for arranging the sessions, to Cindy for refreshments and to Colin for his time, expertise and enthusiasm.

Jenny Gibb

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