Hydrangeas: consistent colour
The most interesting and reliable hydrangeas for late-season flowering. Written by Sarah Morgan.
The first in the parade of late summer flowerers, hydrangeas are a welcome sight after our gardens have gone through that jaded stage towards the end of July. There are hundreds of varieties to choose from, and their colourful flowers come in many shapes, most notably mophead (balls), lacecap (flat) and panicle (conical).
Hydrangeas are mainly found as medium to large shrubs (between 1-3.5m tall) that grow best in a moisture-retentive soil and the sort of shade you find in north, west or east-facing sites. They’re also good to grow under deciduous trees, where their big flowers cheer up the shade. Alternatively, where space is an issue, there are lesser-known cultivars of , sized from 40cm upwards that make useful edging plants for paths or borders.
In recent years, breeders have hit the jackpot with ‘Annabelle’ AGM. Its enormous creamy flowers have a unique decadence so it’s not surprising designers are so stuck on it and new varieties like ‘Incrediball’ are tempting us with ever more extravagant flowers.
Grown for its football-sized flowers on 1-2m tall deciduous shrubs from July to September. New cultivars include ‘Invincibelle Spirit’ and H. arborescens ‘Incrediball’, bred to be sturdier and later flowering. Cut them back hard in spring and you’ll get the biggest flowers. Prune less and the flowers will be smaller and come out earlier.
The aristocrats of the family. They make wonderful specimen shrubs or small trees 2-4m tall with lacecap flowers of a rare intensity of colour unaffected by pH levels. This is the closest to blue you’ll get on alkaline soil. New cultivars like H. aspera ‘Koki’ have burgundy foliage.
There are hundreds of cultivars of this 1-2m tall shrub with either mophead or lacecap flowers in that classic candy pink, white, red or blue when soil is below pH6. New introductions are broadening their appeal, like H. macrophylla ‘Zorro’ AGM or two-toned flowers of H. macrophylla ‘Love You Kiss’ AGM. Still the best white mophead is H. macrophylla ‘Madame Emille Mouillière’ AGM.
These have spectacular panicles of creamy white flowers from July to October, which age into beautiful shades of pink. They are relatively drought tolerant and are a good choice for sun or part-shade. In the 2008 RHS Wisley Trials of H. paniculata, ‘Phantom’ AGM was the winner.
These are planted for their brilliant autumn leaf colour and white panicle flowers from July to September. Try 2m tall H. quercifolia ‘Snowflake’ (‘Brido’) AGM or the 1m tall H. quercifolia ‘Pee Wee’.
The Japanese love their dainty leaves and lacecap flowers and, ranging from 40cm tall, they’re a great choice for smaller gardens. They often have purple-red autumn foliage that contrasts well with their flowers. One good cultivar is H. serrata ‘Dolmfy’.