Before the garden truly loses its summer colours and the nights are too chilled, it is time to snip away green growth and take cuttings. Semi-ripe cuttings are deliciously easy: ripened over the summer, these are so willing to choose life that you merely have to wave them at free-draining conditions and out their miraculous roots creep.
With a little care over winter, you can by spring have a whole gang of new plants to establish. The best subjects for semi-ripe cuttings are the things that survived the drought and the heatwaves – the things your garden needs more of, from Mediterranean perennial herbs such as rosemaries, lavenders, thymes and sages, to late-summer salvia and the verbenas, both trailing and upright.
A one-litre pot plant of a choice salvia, such as Amistad or Lake Tahoe, costs at least £10 – double that for a bigger one, so it makes economic sense to take cuttings now. Or splurge on one or two choice cultivars and have a dozen plants for next summer.
A choice Salvia costs at least £10 to buy, so it makes good economic sense to take cuttings now
A semi-ripe cutting at its most basic is a shoot severed below a leaf, resulting in a cutting of 10-15cm. There are several versions, such as basal cuttings, where you cut through the slight swelling at the base of a shoot; or a heal cutting (particularly good for slightly more woody rosemaries and sages), where the cutting is pulled away from the main stem so that a little piece of it comes away too.
All cuttings need to be taken from shoots that are not flowering or in bud. The best semi-ripe basal cuttings are a good healthy green colour and sturdy in growth. Whippy, weak material does not take well. Spend your money on good-quality peat-free compost, preferably peat-free John Innes No 1, which is formulated for seeds and cuttings and not too rich in nutrients.
If you can’t get hold of this, you need to cut the best peat-free compost you can buy with something free-draining by 50%, be that horticultural (never building) sand or coarse grit. The quickest way to kill a cutting is to sit it in a slump of wet compost. This is also why you place cuttings around the edge of the pot rather than in the centre, as the edge gives better draining conditions.
Cuttings are best taken in the morning, and the compost will need to remain damp: this is most easily done by covering the pot with a clear plastic bag and positioning it somewhere warm, but out of direct sunlight. Autumn cuttings take fastest in a heated propagator, but a warm windowsill will work almost as well. Look out for autumn propagation classes at your local open garden or nursery. Once you’ve got the knack, you’ll find it’s quite addictive.