Hydrangeas are a popular garden shrub, with their colorful blossoms lasting for many months. Gardeners must take care of their hydrangeas to keep the shrubs looking compact and neat and to keep the plants healthy. Hydrangea trimming is easy, but gardeners must know what type of hydrangea they have. Plants that bloom on new wood require different pruning from those that bloom on old-growth wood, and a trimming mistake may mean few to no blossoms next year.
Old Wood Bloomers
Check your hydrangea for dead stems, which will be tan or brown in color. Cut off at their base any dead stems you find. Old wood bloomers must be pruned in the summertime and cannot be pruned after August. Pruning in the fall disrupts the following year's bloom.
Remove one-third of the old growth from the hydrangea each year by cutting it off at the base. This helps keep your plant from getting bushy and will rejuvenate older hydrangeas. Do this only with plants five years or older.
Head back branches that have grown too long in June or July, while it's safe to do so without disrupting next year's flower buds. Snip the branches back with your pruners until they are at the desired height.
New Wood Bloomers
Prune away any dead wood from new blooming hydrangeas in the same manner as you would old wood bloomers. This can be done any time of year except in the spring.
Trim off branches that rub up against other branches. Also remove any wayward branches that prevent the hydrangea from having a nice form.
Cut new wood bloomers back to 6 inches above the ground each year if you want. While this means you won't have to look at your dead hydrangea stems in the winter, you may have to stake the stems for support when your hydrangea begins to bloom again. Some gardeners may prefer to avoid staking and can leave the hydrangea alone after performing the basic maintenance described above.
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Based in Northern California, Elton Dunn is a freelance writer and nonprofit consultant with 14 years' experience. Dunn specializes in travel, food, business, gardening, education and the legal fields. His work has appeared in various print and online publications. Dunn holds a Master of Fine Arts in creative writing and a Bachelor of Arts in English.