September is a useful time in much of the UK to take semi-ripe cuttings from suitable shrubs and herbs. Choose healthy shoots grown this year: firm at the base but still soft at the tip. Hardwood cuttings of many deciduous shrubs come later, after leaf fall, and root cuttings of certain perennials are usually taken from mid-autumn into winter. The plant and its condition matter more than a fixed date.
Hi there, fellow DIYer,
If you already have a shrub you like, taking a few cuttings can give you more plants without buying another established specimen. The trick is to match the method to the plant and season. A lavender shoot in September and a leafless dogwood stem in November need different treatment.
Here is the practical route, with the sources I used at the end.
Which type of cutting should you take?
| Type | Usual UK timing | Material | Examples |
|---|---|---|---|
| Semi-ripe | Late summer to early autumn | This year’s stem, firm at the base and soft at the tip | Lavender, rosemary, hebe, hydrangea, box and many evergreen shrubs |
| Hardwood | Mid-autumn to late winter, after leaf fall for deciduous plants | Dormant, woody stem from this year’s growth | Dogwood, forsythia, flowering currant, willow and some roses |
| Root | Mid-autumn to early winter, while dormant | A suitable section of root | Oriental poppy, globe thistle, bear’s breeches, phlox and verbascum |
The RHS guide to semi-ripe cuttings lists several plants that can be propagated this way. The hardwood and root-cutting guides cover the later methods. Check advice for your exact species or cultivar before cutting into a valuable plant.
Semi-ripe cuttings: the September job
A semi-ripe cutting is neither floppy new growth nor fully hard wood. Look for a healthy, non-flowering shoot grown this season with a firm base. The RHS recommends collecting cuttings in the morning, using sharp, clean secateurs, and putting them straight into a plastic bag in the shade. Aim to prepare and pot them within 12 hours.
What you need
- Sharp, clean secateurs and a clean blade for the final cut.
- Small pots or a propagation tray with drainage holes.
- Peat-free cuttings compost, or a free-draining mix of equal parts peat-free potting compost and horticultural sharp sand.
- A clear bag, propagator or greenhouse to maintain humidity, plus labels and a pencil.
Horticultural sharp sand is sold for potting mixes; it is not the same as builders’ sharp sand. The compost must drain well while staying damp.
Prepare and pot the cutting
- Choose healthy growth with no obvious pest or disease damage. Avoid unusually vigorous, soft shoots.
- Trim a basic cutting to about 10 to 15 cm, cutting just below a leaf node. Remove the lowest leaves and any soft tip. On a large-leaved shrub, halve the remaining large leaves to reduce water loss.
- Fill a pot with moist, free-draining cuttings compost. Make a hole first so the base is not damaged as you insert the cutting.
- Insert the cutting, firm the compost gently around it, water well and let the pot drain. Label it with the plant and date.
- Cover with a clear bag or use a propagator. Keep it in bright light out of direct sun. Remove excess condensation and ventilate if mould develops, while keeping the compost damp rather than waterlogged.
A heel cutting is another option for some shrubs: the side shoot is pulled away with a small piece of older stem attached. The RHS cites ceanothus and berberis as examples. Use the method recommended for the plant you are propagating rather than assuming every species responds the same way.
What happens next?
Rooting time depends on the plant and conditions. Cuttings kept in a greenhouse or propagator may root faster than those in a cold frame. Some hardy shrubs rooted outdoors may not have a full root system until the following spring. Remove dead or diseased material promptly and keep checking moisture.
Before moving a rooted cutting outdoors, harden it off gradually. The RHS suggests two to three weeks for cuttings rooted in a greenhouse or propagator. Pot on when the roots have developed enough to hold the compost together, rather than following a fixed calendar date. Tender plants need a light, frost-free place through winter; hardy plants still need suitable protection from waterlogging and severe weather.
Hardwood cuttings: keep this job for later
For many deciduous shrubs, wait until the leaves have fallen and the plant is dormant. Avoid periods of severe frost. The RHS recommends healthy, woody but pliable shoots from the current year’s growth.
- Cut the shoots into sections around 15 to 30 cm long, depending on the plant and growing space.
- Make a sloping cut above a bud at the top and a straight cut below a bud at the base. The different cuts show which end goes up; the sloping top helps shed water.
- Put the cuttings into a prepared outdoor trench or a deep pot of suitable compost, with only the upper buds above the surface. Water them in and keep them labelled.
- Leave them to root without repeated disturbance. Some hardwood cuttings take many months and are best left in place until the following autumn.
Dogwood, forsythia, flowering currant and willow are among the plants in the RHS hardwood-cuttings guide. Evergreen plants can require a different technique even when cut at a similar time of year, so check the species guidance.
Root cuttings: only for suitable plants
Root cuttings suit plants that can produce new shoots from their roots. The RHS root-cuttings guide lists oriental poppy, phlox, globe thistle, bear’s breeches and verbascum. Take them when the parent plant is dormant, usually in mid-autumn or early winter. Start with a vigorous, healthy plant.
- Lift the plant, or expose part of its root system where the species dislikes disturbance. Wash enough soil away to identify healthy roots.
- Remove no more than one-third of the root system and replant the parent promptly.
- For thick, pencil-sized roots, make 5 to 10 cm
Typical lengths from the RHS guides. Check the advice for your exact plant. pieces. Cut the upper end straight and the lower end at an angle so their orientation stays clear.
- Stand the pieces upright in free-draining cuttings compost, with the straight-cut upper end just below the surface. Top-dress with grit, water lightly and place the pot in a cold frame.
- In spring, pot up individual plants only when they show growth and are well rooted.
Thin-rooted plants such as phlox need a different method: the RHS recommends longer sections laid horizontally under a shallow covering of compost and grit. Sea holly has a taproot and can resent disturbance, so do not lift it as if it were a clump-forming perennial. Root cuttings are also unsuitable for preserving variegation in plants whose leaf pattern is not carried in the roots.
Why cuttings fail
- The material is wrong for the season. A soft, floppy stem and a dormant hardwood stem need different methods.
- The shoot wilts before potting. Collect in the morning, keep it shaded and prepare it promptly.
- The compost is waterlogged or dries out. Aim for moisture and drainage together.
- The cover is left in strong sun. A bag or propagator can overheat quickly.
- Diseased material stays beside healthy cuttings. Remove it and keep tools and containers clean.
- You move plants before they have rooted. Check for an established root system and harden off protected plants gradually.
Taking extra cuttings gives you room for some failures. Success varies by species and conditions, so a fixed success percentage would be misleading.
Can you propagate a protected variety?
Some named varieties have plant breeders’ rights. In the UK, section 8 of the Plant Varieties Act 1997 provides an exception for acts done privately and for non-commercial purposes. Selling or offering propagating material of a protected variety can require the rights holder’s permission. Check the variety’s protection and any licence terms before selling cuttings. A trademark symbol alone does not establish whether plant breeders’ rights apply.
The simple September plan
Choose one or two healthy plants suitable for semi-ripe cuttings. Take a few labelled shoots, use clean tools and free-draining compost, and keep the pots damp, humid and shaded from direct sun. Note what roots well in your own garden. When the leaves fall, return to the deciduous shrubs for hardwood cuttings; leave suitable root cuttings until dormancy.
If you need a cold frame, workbench or planters for the new plants, browse Fred’s DIY Plans for project ideas and check the available plans before choosing a build.
Best wishes from Fred Schouten