When to Prune Hydrangeas
by Karen Weiland, Advanced Master Gardener
One of the questions I get asked the most is when to prune hydrangeas. Hydrangeas do not need to be cut back to live a long, floriferous life, however, there may be times that it will need to be trimmed. Knowing what type of plant you have and knowing if your plant blooms on old or new wood is a tremendous help.
What is “old and new” wood? Stems are called old wood if they have been on the plant since the summer before the current season. New wood are stems that develop during the current season.
Prune Hydrangea macrophylla, otherwise known as Big Leaf, Mop Head and Lacecap, and Hydrangea quercifolia, otherwise known as oak leaf, after they have finished flowering but do it before August which is when these hydrangeas begin producing flower buds for the following summer. They all produce blooms on old wood. When siting these types of hydrangeas, try to plant them in a space where they can grow to their expected size. There may be times that you will need or want to prune even a well placed hydrangea to increase bloom size, to remove all of the dead or damaged stems or to revitalize an older plant (after 5 years).
Hydrangea paniculatas include varieties such as Limelight and Vanilla Strawberry and Arborescens include varieties such as Incrediball and Annabelle. These types produce mainly white and green shades of flowers and bloom on new growth, meaning they can be pruned in late fall to early spring before they begin to form new flower buds.
If you need help identifying what type of Hydrangea you have, visit this website www.hydrangeashydrangeas.com/identify.html
As always, Happy Gardening!
More information is available online at www.hort.purdue.edu/ext/garden_pubs The Purdue University Cooperative Extension Service can be reached at 499-6334 In LaGrange Co., 636-2111 in Noble Co., 925-2562 in DeKalb Co. and 668-1000 in Steuben Co.
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