How do I cut back a badly overgrown shrub?

Which shrubs tolerate hard renovation and which will die, the three-year staged method, and how to bring a plant back without losing it.

Difficulty: intermediate
Time: 2 hr
Read: 3 min

Short answer

Most deciduous shrubs regenerate from a hard cut; most conifers do not. Where a shrub will take it, either cut the whole thing to about 300mm in late winter and accept two flowerless years, or remove a third of the oldest stems each year for three years and keep flowering throughout.

The critical question is whether a species has dormant buds in old wood. Yew, box, hazel, hawthorn, laurel, philadelphus, forsythia and most deciduous shrubs do. Leylandii, thuja, juniper, lavender, cistus and most broom do not, and cut into bare wood they stay bare permanently.

What you'll need

Loppers
Pruning saw
Secateurs
Gloves and eye protection

Step by step

Establish whether it can regenerate.Deciduous shrubs and yew, box and laurel among evergreens almost all reshoot from old wood. Conifers other than yew, and Mediterranean subshrubs like lavender, rosemary and cistus, do not.
Choose the season.Late winter for most deciduous shrubs, before growth starts. Spring-flowering shrubs can also be renovated straight after flowering. Evergreens in mid to late spring.
Check for nesting birds.It is an offence to damage an active nest. Look carefully, and postpone into autumn if the shrub is occupied.
Decide between one-hit and staged.One-hit renovation is faster and gives a better shape but loses one to two years of flowering. Staged renovation over three years keeps the plant looking like a plant throughout.
For one-hit renovation, cut low and clean.Take everything down to about 300 to 450mm, cutting to outward-facing buds or clean stubs. Remove all the brush.
For staged renovation, take the oldest third.Each year, cut a third of the thickest, oldest stems right down to the base. The remaining two-thirds carry flowers while the new growth comes.
Feed, mulch and water afterwards.Renovation is a large demand on the plant. A general fertiliser in spring, a compost mulch, and watering through the first summer are not optional.
Thin the regrowth the following year.Hard pruning produces a thicket of shoots. Select the best-placed four or five and remove the rest, or you rebuild the congestion you just cut out.
Deal with laurel and privet differently.Large-leaved evergreens like laurel look terrible cut with a hedge trimmer, which slices leaves in half. Cut back to a joint with secateurs or loppers instead.
Accept when the answer is removal.An overgrown leylandii, a split old lavender or a badly diseased shrub is better replaced. Renovation is not a universal solution.

Tips

Yew is the exception among conifers — it regrows from bare wood readily. Nothing else in that family does.
Staged renovation over three years keeps the garden looking like a garden.
Thin the regrowth in year two or you have simply made a denser thicket.

Common mistakes

Hard-pruning a conifer hedge or shrub into brown wood — Leylandii, thuja and juniper have no dormant buds in old wood, so the cut never regrows and the bare patch is permanent.
Renovating and then ignoring the plant — A shrub cut to the ground is drawing on its roots to rebuild. Without water in the first summer and a spring feed, many die in the year after renovation rather than during it.

If it doesn't work

No regrowth after a hard cut

Cause: Species without dormant buds in old wood — Fix: Nothing can be done. Replace it, and check regeneration ability before cutting the next one.

Thicket of weak shoots from the cut

Cause: Normal response to hard pruning — Fix: Thin to four or five well-spaced strong shoots the following winter.

Shrub died the summer after renovation

Cause: Drought stress while rebuilding — Fix: Water renovated shrubs thoroughly through their first summer and mulch.

No flowers for two years

Cause: One-hit renovation of a shrub that flowers on old wood — Fix: Expected. Staged renovation avoids it next time.

Questions people ask

Which shrubs can I cut back hard?

Almost all deciduous shrubs, plus yew, box, laurel, privet and holly among evergreens. Not leylandii, thuja, juniper, lavender, rosemary, cistus or broom.

When is the best time?

Late winter for most deciduous shrubs, before bud break. Spring-flowering shrubs can also be done straight after they flower. Evergreens in mid to late spring.

Will it flower next year?

After a one-hit renovation, usually not for one or two years. Staged renovation over three years keeps some flower every year.