Nobody ever said that pruning hydrangeas was simple and straightforward. But it’s not that complicated either. Given my extensive gardening experience, I thought I had it down – and maybe I did. But I still messed up in a big way.
For Love of Hydrangeas
I happen to love hydrangeas. They are truly workhorse shrubs in the garden, and there are so many varieties that you never get tired of them. I first met and fell in love with mopheads (Hydrangea macrophylla) in France, where they are known as hortensias. Their snowball-shaped flower clusters can be as big as grapefruit.
After that, I transferred my affection to the lacecap variation of the bigleaf. Each florescence is a flat circle of short flowers surrounded by lacy longer blossoms to form a little “cap.”
Slowly I met and loved other species, the oakleaf hydrangea (Hydrangea quercifolia), native to the United States with its loose blossoms and lobed leaves was my darling for a time, but then I came to know and love the vine or climbing hydrangea (Hydrangea anomala).
Truth to tell, I never met a hydrangea I don’t like. I have smooth hydrangea (Hydrangea arborescens) and panicle hydrangea (Hydrangea paniculate) and lots of cultivars of the different types.
Overview of Pruning Hydrangeas
The trick to pruning hydrangeas is to know whether they bloom on new wood or whether they bloom on old wood. Those that bloom on old wood must be pruned soon after their blossoms fade because they start to set next year’s flower buds quickly. Oakleaf, vine hydrangea and bigleaf all bloom on old wood.
Those that bloom on new wood produce buds on the current season’s growth. They can be prunes at any time in winter all the way up to early spring. The two best-known hydrangea species that bloom on new wood are panicle and smooth hydrangea.
Initially, when I just grew bigleaf and oakleaf, life was easy. They all got pruned right after blooming. But as I added more species to my collection, things got more complicated. I managed to keep my head above water until one year when I left my garden in the hands of a neighbor.
Making a Mess of It
One year I left my house and garden in France and headed off to San Francisco to get my MFA (Master of Fine Arts) degree. I asked my nearest neighbor whether he would care for my garden, and he agreed. The tasks included watering the plants through summer until the fall rains began, pruning the shrubs, and weeding.
I had total confidence in my neighbor because he had an utterly lovely garden. But, still, I made a map of my hydrangeas and labeled those that had to be pruned after flowering and those that could be pruned in early spring. I got fancy about it, identifying the shrubs and taking photos of each one to tape onto the map.
Unfortunately, I got distracted when I was assembling the map and mixed up the photos. I arranged them exactly wrong so that the one smooth and two panicle hydrangea shrubs were labeled for late summer pruning, and the bigleaf, oakleaf, and vine hydrangea were all labeled for spring pruning.
My neighbor had promised to follow my instructions to the letter, and he did so. It was all my fault the next summer when my hydrangea looks sadly empty of flowers. My only defense is that I was busy, but that didn’t help my shrubs recover any sooner.
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Teo Spengler has been gardening for 30 years. She is a docent at the San Francisco Botanical Garden. Her passion is trees, 250 of which she has planted on her land in France.
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