Conifer hedging
How to grow a leylandii hedge
× Cuprocyparis leylandii
Leylandii grows up to 90 cm a year on almost any soil in sun, and makes a 2 m screen in three or four years. Plant pot-grown plants under 1 m tall, 60 to 90 cm apart, between October and March. What decides success is trimming: start in the first year, cut two or three times every year between April and August, and never cut back into brown wood, which does not regrow.
- Hardiness
- Fully hardy
- Position
- Full sun to part shade
- Soil
- Most soils; free-draining
- Ideal pH
- 6.0 to 7.5
- Water
- Moderate while establishing
- Feeding
- Moderate feeder
Sowing and planting a leylandii hedge
WhenPlant Oct to Mar (containerised any time); trim Apr to May and Aug
Starting off
Plant pot-grown stock Oct to Mar, or any time with weekly watering; buy plants under 1 m tall, as larger ones rock and fail. Propagate by 10 cm semi-ripe cuttings in Sep to Oct in gritty compost in a cold frame with bottom heat at 18°C, rooting in 3 to 6 months. Stake with a short cane for the first year in exposed sites. Consider western red cedar (Thuja plicata) instead, since it regrows from old wood and leylandii does not.
Spacing and planting
Left unchecked it reaches 30 m by 10 m, so decide its final height before planting and keep it under 2 m to stay inside the High Hedges rules of the Anti-social Behaviour Act 2003 (over 2 m, neighbours can complain). Plant pot-grown stock 60 to 90 cm tall at 60 to 90 cm apart in a single row, 2 m from paths and 5 m from buildings on shrinkable clay, with the rootball level with the surface. Not a container plant.
Varieties worth growing
- Green Leyland cypress
- The plain green hedging conifer and the fastest of the group. Dense, tolerant of wind and salt, and only as much trouble as you let it become.
- 'Castlewellan'
- Golden-yellow new growth that bronzes in winter. A little slower than the green, which makes it easier to keep at 2 m.
- 'Gold Rider'
- The brightest and most lasting gold, colouring best in full sun. Slower again and neater in habit.
A leylandii hedge month by month
Timings are for central England. Allow two weeks later in the north and on cold, heavy soil.
- January
Plant pot-grown stock in open weather. Water young hedges if the winter is dry.
- February
Plant. Decide the final height now, not when it has passed it.
- March
Feed hedges in their first three years and mulch. Last of the dormant-season planting.
- April
First trim late in the month, after checking for nests.
- May
Trim if not done in April. Look for the first brown patches from cypress aphid.
- June
Water hedges planted since autumn weekly in dry spells.
- July
Optional middle trim in a strong growing year.
- August
Final trim of the year, finished by the end of the month.
- September
No more trimming. Take semi-ripe cuttings.
- October
Planting season opens. Stake new plants on exposed sites with a short cane.
- November
Plant. Check ties and canes after gales.
- December
Nothing to do.
Feeding a leylandii hedge
A moderate feeder only while it is establishing. Feed for the first three springs, then stop: an established leylandii needs holding back, not pushing on.
Moderate while establishing, a balanced spring feed; very vigorous.
Feeding plan
At planting, October to March
5 g per litre of root ball: 10 g for a 2 litre pot, 25 g for a 5 litre pot, rubbed onto the outside of the root ball before it goes in the hole. Once only.
March, years 1 to 3
100 g per metre run: the label's 100 g/m² over a strip 1 m wide along the hedge, watered in.
March, years 1 to 3
Garden compost
A 5 cm mulch over the strip to hold moisture through the first summers.
Year 4 onwards
Nothing
No fertiliser. Control the hedge with the trimmer.
Signs to watch
Uniform pale yellow-green growth on a young hedge
Nitrogen hunger on poor soil
Balanced feed at 100 g per metre run in Mar for 3 years only
Bronze-brown foliage overall in winter
Cold and drought stress on a windy site
Water in dry winters and mulch; the green returns by May
Yellow foliage with green veins on chalk
Iron lock-out, rare
Chelated iron
Pests, diseases and problems
Shoots yellow in summer and turn brown by late summer, often on the lower half, with black sooty mould on the stems
Cypress aphid feeding on the shoots earlier in the year; the foliage dies after the aphids have gone
No cure once brown. Keep the hedge trimmed lightly and regularly, which seems to reduce attacks, and tie neighbouring green shoots across small gaps. Large dead areas rarely refill.
Brown patches or a brown face after trimming
Cutting past the green growth into old wood, or trimming in hot dry weather or in autumn
Take only the current season's green growth, trim between April and August, and choose a cool overcast day. Bare wood will not sprout again.
Scattered branches turn yellow then brown, with sunken patches oozing resin on the stem below
Coryneum canker, a fungal disease that enters through wounds
Cut the branch out well below the canker in dry weather and clean the saw. Badly affected plants are best replaced.
A whole plant fades to straw colour and dies, sometimes followed by its neighbours
Phytophthora root rot on wet ground, or honey fungus; check the base of the trunk for a white sheet of fungus under the bark
Remove the dead plant with its roots. Improve drainage for root rot. After honey fungus replant with yew, which is rarely attacked.
Foliage bronzes all over in a cold, dry winter on a windy site
Winter cold and drought stress
Water young hedges in a dry winter and keep a mulch on. The colour returns by May.
Pruning
Pruning and care
Trim Apr to May and again in Aug, taking 10 to 15 cm of green growth each time, and once more in late Jul in a growthy year; never cut back into brown wood beyond the green, as it will not regrow, leaving a permanent bare patch. Taper the sides so light reaches the base. Stop the leaders at 15 cm below the intended final height so the top fills out. There is no renovation for an overgrown leylandii; it
Good to knowExtremely fast, trim at least twice a year and never cut into bare brown wood (it won't regrow). Keep the height in check.
Growing a leylandii hedge in pots
Leylandii is not a container plant. A tree that wants to reach 30 m fills a pot with root in one season, dries out daily and browns from the base, and the brown never regreens. For a conifer in a pot choose a slow yew such as 'Standishii'.
A leylandii hedge: common questions
Why is my leylandii hedge going brown?
Brown patches are usually caused by cypress aphid, by trimming into old wood, or by trimming in hot weather or autumn. Whole plants dying point to root rot or honey fungus. Whatever the cause, brown leylandii does not regrow from bare wood, so small gaps have to be covered by tying in green shoots from either side.
How tall can a leylandii hedge legally be?
There is no fixed legal height limit. Under the high hedges rules in Part 8 of the Anti-social Behaviour Act 2003, which apply in England and Wales, a neighbour can complain to the council about an evergreen hedge over 2 m that harms the reasonable enjoyment of their property, and the council can order it to be reduced. Keeping the hedge at 2 m or below keeps you out of that process. Scotland and Northern Ireland have their own, similar high hedge laws.
How fast does leylandii grow?
Up to 90 cm a year in height once established, which is why it must be trimmed every year from the start. Left alone it will pass 10 m in under twenty years and reach 30 m in time.
Sources
Growing information on this page was checked against these references in November 2026. Feeding rates are Dr Forest label rates.