Willow is one of the most forgiving plants you will ever propagate. Push a pencil-thick length of dormant stem into damp ground in winter and, more often than not, it will root and shoot away by spring. No propagator, no heat mat, no fuss. If you have never taken a hardwood cutting before, willow is the place to start.
Why Willow Roots So Readily
Willows (Salix) have a knack that most shrubs lack: dormant stems can produce roots straight from the wood, without any help from you. It is the same trait that lets a low-hanging branch root where it touches damp soil. You do not need rooting hormone, though a dip in powder or gel does no harm if you happen to have some.
That ease makes willow useful for far more than one tree. The same technique gives you hedging, a quick windbreak, a screen for a compost heap or wheelie bins, woven plant supports, rods for basketry, and coloured winter stems for cutting. Willow also holds soil together on a bank that is threatening to slip.
When to Take Willow Cuttings
Take hardwood cuttings while the plant is dormant, roughly from November to March. Late autumn and midwinter are the best windows, before the buds begin to swell. Pick a mild day when the ground is neither frozen nor under water.
If a cold snap arrives mid-job, you need not rush. Stand the cuttings upright in a bucket with an inch or two of water, or roll them in damp newspaper, and keep them somewhere cool and frost-free — an unheated shed or garage is ideal. Plant them within a few days.
Choosing and Preparing the Wood
Pick the right shoots
Look for the current season's growth: long, straight whips about the thickness of a pencil. Avoid wispy tips, which have little stored energy, and old, thick branches, which root poorly. Choose clean, healthy wood with no canker, rust or dieback.
Cut and prepare
Work with sharp secateurs and make each cut cleanly rather than crushing the stem.
- Cut your whip into lengths of 20–30cm (8–12in), each with at least three or four buds.
- Make a flat cut just above a bud at the top of each cutting, and a slanted cut just below a bud at the bottom. The slant is a memory aid: it tells you which way up the cutting goes once it is in your hand.
- Strip off the lower buds and any leaves, leaving two or three buds on the section that will sit above ground.
- Keep every cutting the same way up — buds pointing skywards — in a bucket of water or damp newspaper. Willow will sometimes root upside down, but it wastes energy and you end up with an odd, twisted plant.
- Plant as soon as you can. If you are delayed, heel the cuttings into a spare patch of soil in bundles.
Planting: Pots or Open Ground
In pots
Use a deep pot — a two-litre pot or a root trainer — rather than a shallow seed tray. Fill it with loam-based compost mixed with grit or sharp sand. Willow wants moisture, but it sulks in airless, sodden compost, so drainage matters.
Push the cutting in so that roughly two-thirds is buried: about 15cm in the compost, with two or three buds above the surface. Firm it in and water well. Stand the pot outdoors in a sheltered spot, out of strong midday sun. It needs cold, not warmth; a windowsill is the wrong place. Roots should appear within a few weeks and shoots in spring.
In open ground
Choose a spot that stays reasonably moist, in sun or light shade. Clear perennial weeds first, then either push the cutting into soft soil or make a slit with the back of a spade and drop it in. Bury the bottom 15cm, firm it, and water.
Space hedging plants 30–45cm apart; for a screen or a specimen tree, give them a metre or more. Mark the row with a cane or two so you do not hoe the cuttings off before they shoot.
Aftercare in the First Year
Willow grows fast, and that speed has a price: it needs water.
- Water new cuttings well through their first spring and summer, especially in dry spells.
- Keep grass and weeds clear of the stems — willow does not compete well while it is establishing.
- Mulch around the plants after planting, keeping the mulch clear of the stem itself.
- Protect new shoots from rabbits and deer with a spiral guard; they find willow irresistible.
- Skip the fertiliser. Rich soil pushes soft, floppy growth that snaps in the wind.
- If you are growing willow for coloured winter stems, cut the whole plant back hard in March, once it is established.
Plants in pots are the exception to any relaxed approach: willow fills a pot with roots quickly and then dries out within a day. Plant it out or pot it on within a year, and check it daily in hot weather.
Siting Willow Wisely
Willow roots travel in search of water, so give them room. Keep them well away from drains, soakaways, sewer pipes, foundations, patios and driveway edges. As a rough guide, plant a willow at least its eventual height away from anything you would rather not have invaded — and bear in mind that some willows grow very large indeed.
Choose your variety with the site in mind. Vigorous sorts such as golden willow and common osier make excellent windbreaks and shelter belts, but they are far too big for a small garden. Shrubby types, including purple osier and the compact Salix gracilistyla 'Mount Aso', suit smaller plots and can be kept in check by annual cutting. Weeping willows are usually grafted, so a cutting will not come true to the parent, and they become enormous — best left to parks and big gardens.
