Pruning shrubs, roses and hedges
Cut above an outward facing bud, at the right time for that plant, and take out the dead and crossing growth first.
Cut above an outward facing bud
A cut just above a bud, sloping away from it, sends growth in the direction that bud faces. Choose an outward facing one and the shrub opens up; choose an inward facing one and you get congested crossing growth that then has to be cut out again.
Leave about 5mm above the bud. Closer and the bud dries out; further and the stub above it dies back, which on a rose is where dieback enters the stem.
- Outward facing bud
- It sends new growth away from the centre, which is what keeps a shrub open.
- About 5mm above it
- Closer dries the bud out. Further leaves a stub that dies back into the stem.
- Slope away from the bud
- So water runs off rather than sitting against it. A flat cut holds a drop of water on the bud.
- Opposite buds, cut straight
- On a plant with paired buds a sloping cut favours one and kills the other.
The three Ds first, then shape
Before deciding what shape you want, take out everything dead, damaged and diseased. Then anything crossing or rubbing, because those wounds are where disease enters. Very often that is most of what needed doing and the shrub already looks better.
Only then start shaping, and stop more often than feels natural. Standing back every few cuts is the whole technique, because you cannot see the shape of a shrub from inside it.
- Dead, damaged, diseased
- In that order, and before any decision about shape. Often it is most of the job.
- Then crossing and rubbing
- Two stems rubbing wear through the bark, and that wound is where disease gets in.
- Stand back constantly
- Every few cuts. You cannot judge the shape of a shrub from arm's length inside it.
- Stop early
- You can always cut more next week. You cannot put a branch back on this week.
Timing depends on when it flowers
The rule that covers most shrubs is simple. Anything that flowers in spring on last year's growth is pruned straight after flowering, because pruning it in winter removes the flower buds. Anything that flowers in summer on this year's growth is pruned in late winter or early spring.
Get this backwards and the plant is healthy and never flowers, which is the commonest pruning complaint there is. Hedges are different again and are cut when growth allows, with bird nesting season checked first.
- Spring flowering, prune after flowering
- It flowers on last year's wood, so winter pruning cuts the flowers off.
- Summer flowering, prune late winter
- It flowers on this year's growth, so cutting back hard early gives more of it.
- Cherries and plums in summer only
- Winter cuts on prunus invite silver leaf. This exception matters and catches people out.
- Check for nests, March to August
- It is an offence to damage an active nest, and hedges are exactly where they are.
Bypass, not anvil
Bypass secateurs have two curved blades that pass each other like scissors, slicing the stem. Anvil types close a single blade onto a flat plate, which crushes the stem against it. On living wood a crushed cut dies back and is slow to heal.
Anvil pruners exist and they suit dead wood, where crushing does not matter. For anything living, bypass every time, and keep it sharp, because a blunt bypass blade also crushes rather than cutting.
- Bypass for living wood
- Two blades passing, slicing the stem. Anvil types crush it against a plate.
- Anvil for dead wood only
- Where crushing does not matter. They are cheaper and they are not a substitute.
- Blunt bypass crushes too
- Sharpness is not cosmetic here. A dull blade does what an anvil pruner does.
- Match the tool to the stem
- Secateurs to 15mm, loppers to 30mm, a saw above that. Forcing a tool springs its blades.
Clean blades between plants
Pruning tools carry disease from one plant to the next on the blade. It matters most with roses, fruit trees and box, where canker, silver leaf and box blight all move on a dirty blade.
A wipe with disinfectant between plants takes seconds. If you have just cut out something obviously diseased, clean before the next cut rather than the next plant, and put the prunings in the bin rather than the compost.
- Wipe between plants
- Seconds each time. Roses, fruit and box are where it matters most.
- Clean immediately after diseased wood
- Not at the end of the plant. The next cut is the one that spreads it.
- Bin diseased prunings
- A compost heap that does not get hot enough returns the disease to the garden.
- Oil after cleaning
- Disinfectant strips the oil film, and sap plus bare steel means a pitted blade within weeks.
Frequently asked questions
- What tools do I need for pruning?
- Bypass secateurs for stems up to about 15mm, loppers to about 30mm, a folding pruning saw above that, and hedge shears for soft growth. Add snips for deadheading and gloves for roses. That covers almost all pruning within arm's reach in a domestic garden.
- Where should I cut when pruning a shrub?
- About 5mm above an outward facing bud, sloping away from it so water runs off. New growth follows the direction the bud faces, so an outward facing bud opens the shrub up. On plants with paired opposite buds, cut straight across instead of sloping.
- When should I prune a shrub?
- It depends when it flowers. Spring flowering shrubs flower on last year's growth, so prune straight after flowering. Summer flowering shrubs flower on this year's growth, so prune in late winter or early spring. Getting it backwards gives a healthy shrub that never flowers.
- What is the difference between bypass and anvil secateurs?
- Bypass secateurs have two curved blades that pass each other and slice the stem. Anvil types close one blade onto a flat plate, crushing the stem against it. Use bypass on anything living, since a crushed cut dies back and heals slowly. Anvil types suit dead wood.
- How thick a stem can secateurs cut?
- About 15mm for most bypass secateurs. Beyond that use loppers to about 30mm, or a pruning saw. Forcing secateurs past their capacity springs the blades out of alignment permanently, after which they crush rather than cut whatever their size.
- Should I clean my pruning tools between plants?
- Yes, with a wipe of disinfectant, which takes seconds. Blades carry disease from one plant to the next, and it matters most with roses, fruit trees and box, where canker, silver leaf and box blight all travel on a dirty blade.
- How do I prune a rose?
- Take out dead, damaged and diseased stems first, then anything crossing or thin and weak. Then cut the remaining stems back to an outward facing bud, sloping away from it. Most bush roses are pruned in late winter, and prunings go in the bin rather than the compost.
- When can I cut a hedge?
- When growth allows, but check for active bird nests first, since damaging one is an offence and hedges are where they are. In practice that means avoiding roughly March to August for anything more than a light trim, and doing the main cut in late summer or winter.
