Advice on When to Prune Shrubs – Mostly Wrong?

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In a recent post I mentioned hiring an expert to teach my coop to prune their (damn) shrubs and linked to the pruning instruction that resulted. The shocker to me and most gardeners, I’m betting, is this bit of advice from the professional pruners:

she told us that euonymus can be hand-pruned any time of the year, and that almost all shrubs can be, too.

But-but-but doesn’t EVERYONE tell us to prune flowering shrubs soon after they’ve bloomed, to avoid removing the next year’s blooms? For example, typical advice for azaleas is that “If you prune azaleas after the beginning of July, you may not get any flowers on the bush next year.”

Yes, shearing would remove most or all of next year’s buds if done too late, but shearing azaleas is not advised, anyway.

The expert we hired, from a 29-year-old company whose sole job is to prune shrubs, told us that hand-pruning – for a more natural look, better plant health, and less maintenance – can be done any time the temperatures are above freezing, for all but a few plants.

What a revelation! I’d questioned the narrow timing window for pruning myself. “Hmm,” I said to myself, “if I’m just removing branches and flowers where I don’t want them, what’s the harm?” Or as our expert’s boss told me on the phone, instead of 450 blooms you may have just 420, but they’re where you want them and they’re displayed on a better looking plant. She added that here in the Azalea Belt of the Mid-Atlantic, “If we had to prune all the azaleas within a month after blooming, I’d have to hire 3 times the staff!”

Looks like another case of over-generalization in advising about plants, which may just be my pet rant.

Our expert’s general advice on timing?

When lecturing to garden clubs I always start by saying “the best time to hand prune your shrubs is…when you have time.” Our pruning techniques can be used any time of year (except for 5 shrubs) and they will still bloom beautifully on well shaped visually pleasing shrubs.

If you have the time and find it easy to remember to prune each shrub after it flowers that’s a good strategy too.  As long as you are hand pruning and not shearing, timing is what you want and need it to be.

So what ARE the five shrubs that can’t be pruned just anytime? The very few that should only be pruned in winter are roses, wisteria, buddleia, caryopteris and (sub-shrub) Russian sage.

Photos are of azaleas at the National Arboretum.

5 COMMENTS

  1. And even the exceptions are overly broad. Most of my roses are antiques which flower once, on old wood. I prune out dead branches in spring, but do more vigorous pruning for control (much as I love my roses, I do still need room to get by them) after they bloom.

  2. Thanks for posting this. My mother always said the best time to prune is when your shears are sharp. Nice to know that she was right! And thanks for Garden Rant, which I love for its voices, its practicality and its inspiration.

  3. Generalizations are generalizations. And I think they’re important at first, as it is overwhelming in the early stages of gardening to memorize (and more importantly, truly absorb) so many different techniques. There are gaps of course, but experience with the shrubs we grow fills in those gaps, and as long as we’re taking the time to research those shrubs at the same time, those lessons stick. True with so many things in life – I remember having just a superficial book knowledge of the vocabulary and process of buying a house, and it felt overwhelming faced with it. Once I’d gone through the process, I really got it.

  4. Very good advice and the photos are lovely. I was in a pruning predicament early March as I didn’t know when or how to prune Buddleia. Someone online said wack it down to the ground so I did. I just hope it has enough time to grow back into a bush in my zone 5 garden. The season isn’t very long here. When your mentioned to prune it in winter, do you know how much I should take off? It’s the compact Miss Violet type (4 feet tall) which they sell in our area even though the guide online says it’s really not hardy for zone 5. It will die back and regrow. But what to I do about pruning off the dead growth? Is cutting it back to the ground in winter the right thing to do?
    Thanks!

  5. Great post, thanks. For me, the most difficult thing was to learn to prune rose bushes. Pruning roses after flowering is not particularly difficult. Not only adult roses are cut, but also planted this year. All diseased, dry and weak shoots, buds and flowers are removed from the bushes, leaving no more than five strong, developed young branches growing approximately equidistant from each other on the pink bush – the bush should look, if not symmetrical, then harmoniously. Good luck!

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