10 award-winning (AGM) hydrangeas for gardens

Hydrangeas are well-known and well-loved garden plants. They’re easy to grow, flower for many weeks, and often bring extra interest with their autumn leaves. A number of outstanding cultivars have also been recognised with the RHS Award of Garden Merit (AGM), a mark of quality for reliability and garden performance.

Hydrangeas grow well in most soils, although those with blue flowers are sensitive to acidity – in more alkaline conditions the blooms usually fade to pink or purple. If your garden has limy or chalky soil (with a high pH), it’s best to choose white, pink or red-flowered cultivars. If you’re keen on blue flowers and have soil closer to neutral (pH 7), you can use a hydrangea colourant to enhance and maintain their vivid tones.

A hydrangea of many colours

The bloom on the left was grown in acid soil, the right on alkaline

The flowers of ‘Bluebird’ make way for vivid foliage in autumn, extending the season

Hydrangea serrata ‘Bluebird’ combines colourful flowers and vivid autumn foliage. It's an old Japanese variety  that features 15–17cm (6–7in) lacecap flowers with pink or blue florets, depending on the soil. The flowers open from early July until well into the autumn. As the fertile florets are fertilised, the colourful outer ones bend over to reveal the bright pink colouring on their backs – whatever the soil. Height 1.5m (5ft). Hardiness rating H4.

Taking the limelight

Choose Hydrangea paniculata ‘Limelight’ for long-lasting, colour-changing flowerheads

Hydrangea paniculata ‘Limelight’ is a robust, upright shrub growing, with dark green leaves. In summer, it produces dense, cone-shaped flower clusters that open pale lime green, turning creamy white with a gentle pink flush that deepens as the season progresses. Flowering from mid-July to early October, this striking variety adds long-lasting color and structure to any garden. Height 1.5m (5ft). Hardiness rating H5.

Great for small gardens

© Dorling Kindersley

Scented white flowers open from greenish buds

The flowers turn pink as they age

Hydrangea paniculata PINKY-WINKY (‘Dvppinky’) is one of the best for small gardens. Blooming from early August to early October, the flowers open in lime green and develop yellow tints as they age. They mature to deepest pink, often revealing all the colours in one spike – the effect enhanced by red stems. The flowers also have a spicy fragrance. Flowering time can easily be controlled by hard pruning (to give late flowers) or dead-heading only (for early flowers). Height 1.5m (5ft). Hardiness rating H5.

Flowers from the East

Watch the flowerheads gradually fold back as the summer season progresses

Hydrangea macrophylla ‘Veitchii’ was imported from Japan in the 1860s. Its white lacecaps have florets faintly blushed with lilac, which age to lime green before folding down late in the season to reveal their reddish brown backs. The mass of fertile central flowers are pink in

A bud is a small, undeveloped shoot that contains the potential for new growth. Buds are typically found on stems, where they can be apical (found at the tip) or axillary (found between leaf axils) and may develop into leaves, shoots or flowers.

Saucer-size flowerheads

The flowerheads of Hydrangea macrophylla ‘Madame Emile Mouillère’ reach 20cm (8in)

Hydrangea macrophylla ‘Madame Emile Mouillère’, an old French variety, reveals large 20cm (8in) flowerheads that are distinctive in being so crowded that the individual florets are compressed together but also reveal a touch of elegance as the edges of each floret are prettily serrated. Best out of direct sun, the heads can be weighed down by heavy rain. The pure white flowers open in July, continue well into the autumn and age to palest pink or lime green (generally less blueish than in the photo). Height 1.8m (6ft). Hardiness rating H5.

Charming yet tough

Choose Hydrangea macrophylla ‘Lanarth White’ for exposed parts of your garden

Hydrangea macrophylla ‘Lanarth White’ is one of the best of all lacecaps, and also one of the best hydrangeas for exposed positions, poor soil and by the sea. Blooming from early July to the end of August and beyond, a ring of large pure white florets surrounds a mass of green

A bud is a small, undeveloped shoot that contains the potential for new growth. Buds are typically found on stems, where they can be apical (found at the tip) or axillary (found between leaf axils) and may develop into leaves, shoots or flowers.

Impressive flowers

Consider cutting some of the flowerheads for vase decorations

The heads of free-flowering mophead Hydrangea macrophylla ‘Générale Vicomtesse de Vibraye’ are so crowded with florets that the edges are squeezed together. In fact, if the plant is cut back hard the resulting flowerheads will be so large they will bend over and touch the ground under the weight of rain. So, lighter pruning is advisable. The flowers age to limy green and are good for drying. Height 1.5–1.8m (5–6ft). Hardiness rating H5.

Crimson crush

© visionpictures.com

Long-flowering and striking, expect to see summer-to-autumn drama in the garden

Hydrangea macrophylla ‘Kardinal’ (Teller Series) is a rounded, upright

Deciduous refers to plants (mainly trees and shrubs) that lose their leaves seasonally, usually during autumn. This is a natural process triggered by the season's shorter days and lower temperatures and allows plants to conserve energy during the winter months.

Textured blooms

© Shutterstock

Textured and elegant, Hydrangea aspera ‘Velvet and Lace’ creates a standout display

A large deciduous shrub, Hydrangea aspera (Villosa Group) ‘Velvet and Lace’ has lance-shaped green leaves with a soft, velvety underside. In late summer, it produces slightly domed flower heads up to 22cm (8.6in) wide, with small bluish-purple flowers at the centre surrounded by larger pale mauve-pink florets, creating a textured, elegant display in the garden. Height 2m (6ft 7in). Hardiness H5.

Splendid in semi-shade

Hard pruning encourages the flowerheads of ‘Annabelle’ to grow larger, even up to 20cm (8in) across

The huge, near-spherical flowerheads of Hydrangea arborescens ‘Annabelle’ can be 20cm (8in) or sometimes even 25cm (10in) across. The harder you prune – you can cut the plant down to the ground in spring if you like – the larger the flowerheads will be. Opening from mid-July in pale green, the flowers mature through cream to pure white and then back to pale green in October. Happy in light shade. Height 1–1.8m (3–6ft). Hardiness rating H6.