Pruning 'Summer Crush' Hydrangea in Late Summer or Early Fall

Hydrangea 'Summer Crush' in June...

in September

Pruning can be a complicated project, especially when it comes to hydrangeas (I can think of one more plant that causes pruning headaches - clematis). That said, if you grow many hydrangeas, especially different types, once you get the hang of it, it begins to come naturally.

I used to rarely prune my hydrangeas because I had more space. Now, with a smaller garden, I'm finding that some are getting too large for comfort. Case in point, 'Summer Crush'. It is actually not a huge hydrangea, but it does get larger than advertised - about 5 feet in my garden (the tag said 3-4').

'Summer Crush' is in the 'Endless Summer' line of hydrangeas and they are among the easier to prune. This is because they bloom on both old and new wood. Therefore, no matter when you prune, you should get blooms. It is the older hydrangeas, the ones that only bloom on old wood, that you have to be careful with. I would recommend pruning them immediately after bloom, earlier in the summer.

Here are some tips -

• First, younger hydrangeas don't really need to be pruned at all, except for removing old canes. Space issues are really the only reason for pruning.
• Wait until the hydrangea is 3 years old before you do any pruning.
• Most hydrangeas can be pruned in either late summer or early spring.

'Summer Crush'  has been in the garden for four years. This is the first time I have pruned it. I am a little late in doing this - it is mid-September - normally I would do this in August.

First, I lightly prune the spent blooms so that I can see inside the bush better.

The next step is to cut back the stems anywhere from 1/4 to 1/2. I like to cut back the stems at different levels, so I cut back some by 1/2 and others by 1/2. Do whichever you feel comfortable with. Make the cuts just above a set of buds -

Next, take a closer look at the stems near the bottom of the shrub. As hydrangeas age, the older stems can easily be identified by their thickness, and they will not be as smooth as the newer stems. These older canes should be completely cut down to the ground. This will promote new stems. If you are working on a younger plant, there will not be many stems like this. In this case, I only cut out two of the older stems. 

If you see any stems that are dead, brittle, or pencil-size thickness, cut them out completely.

After pruning, I add a layer of compost (I'm using a 4-way mix, which is a mixture of loam, compost, sand and dairy manure). 

Water well and the hydrangea is ready for winter. The end result -

Text and photos by Phillip Oliver, Dirt Therapy