Many woody plants can be propagated by semi-ripe cuttings taken in mid-late summer. Vegetative propagation is especially useful for increasing stock of named cultivars, which don’t come true from seed.
Semi-ripe cuttings are sections of the current season’s growth that has begun to firm. The cutting base is quite hard, while the tip is still soft. Avoid damaged, unhealthy, over-vigorous or atypical material, selecting shoots that are more horizontal in habit with short internodes. Many unproductive stock plants can be hard pruned to stimulate suitable new growth.
With shrubs and climbers, including Hedera, Lavandula and Choisya, take semi-ripe cuttings from midsummer to autumn.
Select healthy material and use clean tools. Take cuttings in the morning to avoid wilting.
Process
Remove sideshoots of the current season’s growth from
the stock plant using sharp secateurs.
Trim them to 10-15cm (4-6in) in length, cutting just below
a node, then remove the lowest leaves and soft tip.
Dip the cutting base in fresh
rooting hormone powder, ensuring that the basal cut is well
covered; tap off any excess powder.
On large-leaved shrubs, cut the leaf in half to reduce water loss from the foliage. For difficult-to-root shrubs such as Magnolia grandiflora, try removing a sliver of bark 2.5cm long on one side of the stem base to assist rooting.
Insert the cuttings into suitable containers of free-draining compost with 50 percent sharp sand or perlite, and keep in a glasshouse or propagator with bottom heat. Alternatively, cover pots with a plastic bag and put in a warm place, removing excess moisture but keeping compost damp. Remove any dead or diseased material that may appear.
Aftercare
Ensure that the compost remains moist until the cuttings are well rooted, shading the cold frame in hot weather. During winter remove any fallen leaves and dead cuttings, watering only if the compost is dry.
Once cuttings have rooted, harden off for two to three weeks before potting on or planting out. Cold frames, unheated greenhouses or even under horticultural fleece are good places for hardening off.
Sarah Durrant
Further information
International Plant Propagators Society