Nancy Brachey

Pruning hydrangeas can be a tricky job

The popular mophead or florist hydranges should be pruned now, if necessary, so that new growth will produce wood that will bear next year’s flowers
The popular mophead or florist hydranges should be pruned now, if necessary, so that new growth will produce wood that will bear next year’s flowers Leavit Lerner/The Washington Post

Hot as it is, you deserve a break by limiting your gardening to a slow walk to pick a fresh tomato or cucumber for tonight’s salad.

However, a few of you are worried about your hydrangeas, especially the popular ones with the pink or blue flowers that bloom in early summer. I hear that some are overgrown, some are rather rangy and not too shapely.

When to prune? Now.

These hydrangeas, often called mophead or florist hydrangeas, are among the most popular shrubs for shady landscapes. That is partly thanks to this hydrangea being a choice selection for Mother’s Day gifts as well as the rise of the Endless Summer series of hydrangeas.

The typical florist hydrangeas bloom once, in early summer, on wood that grew the previous year, which is why you should prune them now. It will give them time to put out the new growth that will bear next year’s flowers. However, you should not expect an abundance of bloom the next year after a big pruning.

Years ago, my blue hydrangea was in the way of a remodeling project at my house and was cut to the ground. Because it was well-established, it began to grow back quickly, producing a denser, more shapely shrub with excellent bloom.

However, most plants require less drastic work. Start by cutting back any dead stems to the base of the plant. Then, if your plant is older than five years, cut back a third or so of the oldest stems to the base. This should rejuvenate the plant nicely by increasing density and improving the shape. It will also leave stems that will produce next year’s flowers.

A vastly overgrown hydrangea may be cut back overall, but you should not expect much bloom next year, though it will benefit in the long term, as mine did.

The Endless Summer hydrangeas and their relatives bloom repeatedly on both the older growth produced last year as well as the new growth. That is why pruning them is tricky since you are likely to remove flowering wood if you prune now or later.

That is why great care must be taken to plant these hydrangeas where they have space to reach maturity. That will avoid pruning to keep the plant out of doors and windows and you will need to do only occasional rejuvenation pruning. If you prune these plants, cut the oldest stems only, which will protect future blooms.

Nancy Brachey:

Ask Nancy

Q. I saw some plants I want for very good prices, but wonder about setting them out now. Isn’t it too hot?

A. You can take advantage of those prices and enjoy those woody plants. However, once you get them home, I would not set them in the ground for a while. Keep them in their nursery pots, set them in the shade and water them regularly for the next month or so. This will prevent wilting.

Once the summer heat begins to ebb, you can set them in the ground, again taking care to water them regularly while they adjust to their new space.