Join the RHS today and support our charitable work
Free personalised gardening advice
RHS members get reduced ticket prices
RHS members get free access to RHS Gardens
Free entry to RHS members at selected times »
Reduced prices on RHS Garden courses and workshops
020 3176 5800
Mon – Fri | 9am – 5pm
Help us achieve our goals
Join the RHS today and support our charity
Hydrangea scale became established in the UK during the 1980s and has since become widespread in English gardens, it is also found in parts of Scotland and Wales.
Hydrangea scale is a sap sucking insect found on hydrangeas but can also feed on many other woody plants including Acer and Prunus. Infested plants can suffer a lack of vigour and leaf loss caused by the insect sucking sap from the foliage and stems. This is one of many types of scale insects encountered by gardeners.
The immature scales (nymphs known as crawlers) are difficult to see but infestations become apparent in early summer when the mature scales deposit their eggs on the stems and leaves. You may see:
Heavily infested plants can be removed and replacements planted in the autumn. Some manual removal of egg masses and adult scale can be attempted but may have a limited affect.
Control is best attempted in July when the more vulnerable scale nymphs are present. Hydrangeas can be prone to damage from sprays to the leaves, to reduce this risk avoid spraying hydrangeas in hot sunny weather or if the soil is dry.
Pesticides for gardeners (Adobe Acrobat pdf document outlining pesticides available to gardeners)
Hydrangea scale is a sap-sucking insect that develops on the underside of leaves on Hydrangea and other host plants.
There is one generation a year with young nymphs hatching from eggs in mid-summer and sucking sap from the undersides of leaves. In late summer the nymphs move to the stems where they overwinter before maturing in late spring. Eggs are deposited under a covering of white waxy fibres in early summer.
Chemical labels explained
Chemicals: using a sprayer
Chemicals: using safely and effectively
Horse chestnut scale
RHS statement on pesticides in horticulture
Scurfy rose scale
Woolly vine or currant scale
the RHS today and get 12 months for the price of 9
RHS members can get exclusive individual advice from the RHS Gardening Advice team.
We're a UK charity established to share the best in gardening. We want to enrich everyone's life through plants, and make the UK a greener and more beautiful place.