How to Grow Hydrangeas: Complete UK Care Guide

Hydrangeas grow well across most of the UK when planted in moisture-retentive, humus-rich soil in a sheltered spot with morning sun and afternoon shade. Choose the right type for your garden, water consistently through summer, and prune according to variety, since mopheads and lacecaps flower on old wood while paniculata and Annabelle types flower on new growth.

Attribute	Detail
Botanical name	Hydrangea spp.
Plant type	Deciduous flowering shrub
Height & spread	1-2.5m depending on variety
Hardiness	RHS H5-H6 (fully hardy, most UK regions)
Position	Partial shade to full sun, shelter from strong wind
Soil	Moist, fertile, humus-rich; acidic for blue macrophylla flowers
Flowering/interest period	June to September, dried heads into winter
Difficulty	Easy to moderate

Choosing hydrangea varieties

There are several distinct groups of hydrangea suited to UK gardens, each with different flower forms, pruning needs and hardiness. Mopheads and lacecaps (Hydrangea macrophylla) are the most popular for borders and pots, while paniculata and arborescens types are tougher and more forgiving.

Variety	Type	Flower colour	Notes
Hydrangea macrophylla 'Endless Summer'	Mophead	Blue or pink (pH dependent)	Reblooms on old and new wood
Hydrangea macrophylla 'Ayesha'	Mophead	Lilac-pink, cupped petals	Distinctive lilac-scented blooms
Hydrangea macrophylla 'Blue Wave'	Lacecap	Blue on acid soil	Delicate flat flowerheads, good for wildlife
Hydrangea paniculata 'Limelight'	Paniculata	Lime-green fading to pink	Sun-tolerant, flowers on new wood
Hydrangea arborescens 'Annabelle'	Arborescens	White	Very hardy, large round blooms
Hydrangea quercifolia 'Snow Queen'	Oakleaf	White ageing to pink	Good autumn leaf colour

Where and when to plant hydrangeas

Plant hydrangeas in autumn or spring when the soil is workable and not waterlogged or frozen. Choose a sheltered position with dappled or morning sun; full midday sun can scorch leaves and dry blooms, especially in southern England. Avoid frost pockets, as late spring frosts can damage emerging shoots and flower buds.

How to plant a hydrangea

1. Dig a hole twice the width of the root ball and the same depth.
2. Fork over the base and mix in well-rotted compost or manure.
3. Soak the plant in its pot with water before removing it.
4. Position so the top of the root ball sits level with the surrounding soil.
5. Backfill, firm gently, and water thoroughly.
6. Apply a 5cm mulch around the base, keeping it clear of the stems.

Watering and feeding

Hydrangeas need regular watering, particularly in the first two years and during dry spells, as they have a shallow root system. Water deeply at the base rather than little and often. In spring, apply a balanced granular feed or well-rotted manure mulch, followed by a potash-rich feed such as tomato fertiliser in early summer to boost flowering.

Changing flower colour

To turn macrophylla flowers blue, keep soil pH below 5.5 using ericaceous compost, sulphur chips or a proprietary hydrangea colourant, and water with rainwater rather than lime-rich tap water. For pink flowers, maintain a neutral to alkaline soil around pH 6.5 and apply lime if necessary. White varieties and paniculata types are unaffected by pH.

Pruning hydrangeas

Pruning timing depends on whether the variety flowers on old or new wood. For mopheads and lacecaps, leave the dried flowerheads over winter as frost protection, then in March cut back to the first strong pair of healthy buds below the old flowerhead, removing a fifth of the oldest stems at the base to rejuvenate the plant. Paniculata and Annabelle types flower on new wood, so cut back hard in late February to a low framework of buds to encourage large blooms. If you use secateurs or a small pruning saw for thicker old stems, keep blades clean and sharp; see our how-to hub for more seasonal pruning guidance.

Propagation

Hydrangeas root easily from softwood cuttings taken in early summer. Select a non-flowering shoot, cut a 10-15cm length just below a leaf node, remove the lower leaves, and insert into free-draining cutting compost. Keep in a humid, shaded spot until rooted, usually within four to six weeks, then pot on individually.

Growing hydrangeas in pots

Compact varieties such as 'Ayesha' or dwarf paniculata cultivars suit large containers. Use a peat-free ericaceous compost if you want to control flower colour, ensure the pot has good drainage, and water more frequently than border-grown plants, as containers dry out quickly. Move pots to a sheltered spot for winter to protect roots from freezing.

Common problems

Problem	Symptom	Fix
Powdery mildew	White powdery coating on leaves	Improve air circulation, water at the base, remove affected leaves
Frost damage	Blackened new shoots in spring	Delay pruning until after last frost, use fleece in cold snaps
Vine weevil	Notched leaf edges, grubs in compost	Use biological nematode control, check pots for larvae
Leaf scorch	Crispy brown leaf edges	Move to a shadier spot, increase watering
No flowers	Healthy leaves but no blooms	Check pruning method matches variety, avoid over-feeding with nitrogen

Month-by-month hydrangea care

Month	Task
January-February	Leave old flowerheads for frost protection; prune paniculata and Annabelle
March	Prune macrophylla types; apply mulch and balanced feed
April-May	Watch for late frosts; protect new growth with fleece if needed
June-July	Water regularly; apply potash feed; take softwood cuttings
August	Deadhead spent blooms where reblooming; keep watering in dry spells
September	Reduce feeding; continue watering
October-November	Plant new hydrangeas; leave old flowerheads on for winter protection
December	Check container plants are protected from hard frost

For more flowering shrubs to combine with hydrangeas in a UK border, browse our plant guides and grow guides hub.