Shrubby hydrangeas

RHS Genus Guide

Shrubby hydrangeas are well suited to borders adding structure and colour from mid-summer onwards. More compact cultivars can be grown in containers. The flowers fade to shades of pink and can last well into the winter months. They form round or conical tightly packed flower heads or flatter flowers with a ring of large flowers surrounding tiny inner one.

RHS/Joanna Kossak

Appearance

Small- to medium-size shrubs, with dome, upright or vase-shapes and handsome, toothed leaves. Mophead types (Hydrangea macrophylla and Hydrangea arborescence) have round, tightly-packed flowerheads. Others (Hydrangea paniculata and Hydrangea quercifolia) have a conical shape. Lacecap hydrangeas (Hydrangea macrophylla, Hydrangea serrata and Hydrangea aspera) have flatter blooms with a ring of large petals surrounding tiny inner flowers.

Preferences

Hydrangeas like moister soils that are not prone to waterlogging. Improving the soil and mulch with organic matter, such as garden compost or a manure-based soil conditioner, will help to keep soil moist. Plant hydrangeas in sun or light shade in a spot sheltered from cold winds.

Dislikes

Growing hydrangeas in very dry soil and full sun can lead to leaf scorch and poor flowering. The new spring growth is prone to frost damage, so plant away from frost pockets and scorching wind.

Did you know?

The flower colour of some hydrangeas changes depending on the pH of the soil (acidity or alkalinity), which is affected by aluminium availability. This can be most often seen in the mophead and lacecap cultivars of Hydrangea macrophylla. Those with naturally blue or pink flowers tend to be bluest in acid soil conditions (high, available aluminium levels), mauve in slightly acid to neutral soil conditions, and pink in alkaline conditions.

RHS Growing Guide