Hardwood Cuttings: The Slit-Trench Method

Cut a leafless, firm shoot of a currant, gooseberry, rose, willow or dogwood any time from mid-autumn to late winter, push two-thirds of it into a slit in sheltered, well-drained ground, and leave it until the following autumn. It needs no propagator, because a dormant cutting has no leaves to lose water through and carries the stored energy it needs to callus and root.

What happens in a dormant cutting

A softwood or semi-ripe cutting, taken from soft growing tissue in spring or summer, is racing against its own leaves: it keeps transpiring with no roots to replace the water, which is why it needs misting, humidity or a shaded propagator. A hardwood cutting, taken from ripened current-year wood after leaf fall, carries no leaves and little active water movement, so that race barely applies.

It draws instead on carbohydrate banked in the wood over the growing season. The base seals the cut with callus, and roots form a little later, mostly from the cambium under the bark and tissue around the cut edge. It is slow: a hardwood cutting can look completely inert for weeks to months, callusing through the winter and rooting as temperatures rise in spring. The trade is speed for reliability, with no misting equipment or propagator.

It only works on plants that root reliably from ripened, leafless wood. Many climbers, shrubs and trees, including fruit, do:

Willow and dogwood are among the most forgiving subjects, which is why willow hurdles, dogwood stooling beds and currant rows are the classic places to see this method at scale. Roses need a little more patience and have a lower success rate. Most conifers and many evergreens do not root this way and need another method.

When: why Scotland's dormancy helps

The window runs from mid-autumn until late winter, essentially the whole dormant season. Avoid taking material in a severe hard freeze.

Bud burst is not set by a date. It follows a chilling period, then spring warmth, with day length a supporting factor, and because that arrives later further north, bud burst runs about one to two weeks later in northern England than in the south and perhaps a further one to two weeks later again in northern Scotland, depending on species. That gives a later safe cut-off for planting a trench in much of Scotland than a general "late winter" instruction implies. Forestry and Land Scotland works to an October to March planting season, because dormancy lets a plant put energy into roots rather than spend stored reserves on leaves and shoots. Frost timing is a related but separate matter driven mainly by altitude and distance from the coast: the frost dates page has the regional picture.

Taking and preparing the cutting

Choose the right wood

Select strong, healthy shoots of the current year's growth, fully ripened and firm, not soft, with plump undamaged buds along the length and no sign of pest or disease. Roughly pencil thickness is the usual target. Avoid old, grey, deeply cracked wood from previous seasons.

Cut to length, the right way up

Remove any soft, unripened growth from the tip, then cut the wood into sections 15 to 30cm long. Make a sloping cut just above a bud at the top, so it sheds water, and a straight cut just below a bud at the base, so the shape tells you which end goes down; an upside down cutting will not root. For pithy-stemmed shrubs such as elder, cut through the heel where the shoot joins its parent branch.

Wounding and rooting hormone

Removing a short sliver of bark from the base exposes more of the cambium and may improve strike rates on less willing subjects. Dipping the cut base in hormone rooting compound is optional: willow roots freely without it, but it is worth doing on roses and other slower rooters.

The slit trench

A sheltered, well-drained spot

Choose a sheltered site with well-drained soil, out of the worst wind and not a low spot that collects water. On heavier soil, put a layer of sand in the base of the trench, a small local fix for the immediate root zone. Adding bulk grit across a whole clay bed takes an impractically large volume and can leave soil harder to manage, so keep the amendment to the trench.

Cut the slit and set the cuttings

Push a spade straight into the ground to its full depth and rock it back and forth to open a narrow slit, a far smaller disturbance than a planting hole. Set the cuttings with about two-thirds of their length below the surface, leaving a bud or two above ground. Space them 10 to 15cm apart, with 40cm between parallel trenches, then firm the soil back round them and water in.

Pots in a cold frame for small numbers

A handful of cuttings, or ground that is too wet or exposed, can go into deep pots of roughly half coarse grit and half multi-purpose compost, in a sheltered cold frame until the following autumn. In cold or exposed gardens a cold frame, clocheA small, portable clear cover placed over an individual plant or short row to trap warmth and keep off wind, rain and pests. Full definition → or unheated shed can also give trench-planted cuttings extra protection through the harshest winter weather.

The two winter hazards on Scottish ground

A slit barely disturbs the soil, so the limit on bare-root tree planting in heavy, wet ground, whether it is workable at all, does not apply in the same way: you can open and close a slit in ground too claggy to dig a planting hole in without wrecking its structure. What does carry over is what happens to that ground once the cuttings are in it.

Frost heave

Repeated freezing and thawing in wet soil lifts recently disturbed ground, cuttings included. Check the trench after any hard frost and firm the soil back around any cutting that has worked loose, rather than leaving it standing proud and drying out. Heavier, slower-draining ground is the likeliest to need this check repeated over a season.

Waterlogging and basal rot

Saturated soil displaces the air roots need, so root function fails and rot organisms move in, at the one point a callusing base is most vulnerable. A trench in a spot that stays wet through winter is better on slightly raised ground, or with sand at the base. A raised bed or a gentle mound is the standard fix wherever winter waterlogging recurs.

What to expect, and when to check

Not every cutting takes, even from a reliable species, so put in a few more than the plants you want. Leave the trench alone once planted: a cutting does not need feeding and should not be disturbed to check progress, apart from the tug test below. The base calluses through winter and roots follow as the soil warms in spring, so new shoots should appear above ground in the growing season. A gentle tug in late summer tells you if it has rooted: resistance means roots. Leave cuttings in place until the following autumn before lifting and transplanting them or potting them on, and keep the ground from drying out completely in a dry summer. Protect anything vulnerable to rabbits, deer or rodents over the first winter, since a leafless stick with no roots has little to recover with if it is grazed or gnawed.

Once rooted, the blackcurrants guide and pruning roses article cover what happens next for two of the most commonly propagated subjects.

Common questions

Sources