The numerous cultivars of Hydrangea paniculata are famed both for their floral flamboyance and intricacy. The masses of conical or cloud-like flowerheads, prominently positioned at the stem tips, offer many months of interest when few shrubs are in flower.
You may also like:
- The best spring flowers to plant
- A spring border planting plan designed by Sarah Price
- 16 garden border ideas
- Sow a border from scratch
- How to prune hydrangea paniculata
What is hydrangea paniculata
This deciduous relative of Deutzia and Philadelphus is a member of a genus of up to 100 deciduous or evergreen shrubs and woody climbers including Hydrangea petiolaris and H. macrophylla. It is notable for displaying two strikingly different types of flowers within the inflorescence, both fertile and sterile – a characteristic of many of its close relatives. Each flowerhead varies in its value to pollinators but the number and size of the flowerheads on each plant often compensate.
Fact file: hydrangea paniculata
- What Deciduous shrub, or occasionally in the wild a small tree, in the Hydrangeaceae family. Commonly known as panicled or paniculate hydrangea.
- Season Midsummer to early spring.
- Size Up to around 8m x 8m.
- Conditions Moisture- retentive soil in full sun or
- part shade.
- Origins Cool temperate and sub-tropical regions of Japan, China and Sakhalin, in sparse forests or thickets.
- Hardiness Hardy throughout most of the UK with an RHS hardiness rating of H5-H6, and suitable for gardens in USDA zones 3a to 8b.
How to grow hydrangea paniculata
When to prune hydrangea paniculata
Cut back all strong main stems by half to three quarters, to a strong pair of buds, after planting. Annually, from February to April, prune back the previous year’s flowering stems, removing dead, diseased, dying, crossing, rubbing and weak growth. Use a saw to cut out old, congested wood. Cut back the stems horizontally, as the buds are in pairs either side of stem.
In borders, hydrangeas work well among plants that will provide interest before they steal the limelight.
Different types of pruning will yield different results. Light pruning, removing the flowerheads, and medium pruning, back to four pairs of buds, produces smaller heads that are greater in number and bloom earlier.
Hard pruning, down to two pairs of buds from the base, produces fewer, larger heads, which may cause weaker stems to flop under the weight, and flower slightly later. Staggered pruning can be used to extend the flowering period for either groups or single plants.
Watch our guide on how to prune hydrangea paniculata
When to plant hydrangea paniculata
Plant when the soil isn’t waterlogged or frozen, or during drought; ideally from leaf fall to bud burst. Autumn planting is best in areas with low spring rainfall.
Plant in moist soil at the same depth it was planted in the nursery, in a sheltered position (avoiding frost pockets and cold winds), in sun or part or dappled shade. If necessary, improve surrounding soil with well-rotted organic matter or leafmould. Mulch after planting with well-rotted organic matter, then annually in spring.
How to take cuttings from hydrangea paniculata
Take hardwood cuttings (15-30cm) just after leaf fall or just before bud burst. Make a horizontal cut below a bud at the base, and a slanting cut away from the buds at the top. Insert the cutting to two-thirds of its length in free-draining soil, or in a pot of compost with a base layer of sharp sand. Don’t let the rooting medium dry out. Transplant the following autumn.
Take semi-ripe cuttings (10-15cm long) from the current year’s wood (midsummer to early autumn) just below a leaf, where the stem has started to harden. Remove the lower leaves and soft tips. Dip in hormone-rooting powder or liquid, and place cuttings around the edge of a pot of 50: 50 mix of peat-free cuttings compost and sharp sand or perlite. Water well. Cover with a plastic bag and place in
a bright position.
Take softwood cuttings (around 10cm long) in spring and early summer from the current year’s new growth, just below a leaf joint. Dip in rooting powder or liquid. Cover the pot in a plastic bag and place in bright sunlight or a propagator at 18-24oC. Rooting takes two to four weeks.
When does hydrangea paniculata bloom
Starting in midsummer, the flowers meld through several colour changes into autumn, when the parchment-like flowerheads remain attractive through winter. Unlike some other hydrangeas, the flower colour of H. paniculata is unaffected by soil pH; they are also notably cold tolerant, down to -30oC, and grow in most soils.
The best hydrangea paniculata varieties
Where to see and buy hydrangea paniculata
- Golden Hill Nurseries Goudhurst Road, Marden, Tonbridge, Kent TN12 9LTHS. Tel 01622 833218, goldenhillplants.com
- Holehird Gardens The Lakeland Horticultural Society, Patterdale Road, Windermere, Cumbria LA23 1NP. Tel 015394 46008, holehirdgardens.org.uk
- Plant Heritage National Collection of Hydrangeas Darley Abbey Park, Darley Abbey, Derby DE22 1EN. hydrangeaderby.co.uk
- RHS Garden Bridgewater Worsley, Salford, Greater Manchester M28 2LJ. Tel 0161 503 6100, rhs.org.uk/gardens/bridgewater
