I’ve written many monthly pruning guides in the past, but some of them are slightly complex and difficult to understand for the average new gardener.
That’s why I’m writing this article – your simplest guide to August pruning. Today, you’ll get exactly what you want, which is to learn what plants you should and shouldn’t cut back during the month of August…without any unnecessary fluff.
Let’s get right into it!
Is Pruning Mandatory?
Well, it’s definitely not mandatory, but it can be extremely helpful!
Since the end of summer is just around the corner in August, pruning during this time can potentially encourage a late flush or blooms, or perhaps a second one if conditions are right.
Self-seeding plants can be restrained by pruning in August, and the removal of dead wood and weak foliage gives the plants some breathing room, limiting chances of disease and humidity-related problems.
What You Can Cut Back In August!
Perennials That Rebloom When Trimmed:
Perennials like catmint, coreopsis, ornamental salvias, and bee balms love hard pruning. In warmer zones, trimming these perennials back by a third in August can lead to a beautiful second flush of blooms before fall really kicks in.
Just the removal of spent flowers and weak stems is enough to get them to start rejuvenating and producing a completely new flush of blooms.
If you’re curious which plants love a good hard chop and actually bounce back stronger, check out this list of perennials that respond best to hard pruning.
Sprawling Or Floppy Plants:
Sprawling perennials like Shasta daisies, veronicas, and yarrow spread quite rapidly. But, while their quick spreading pace ensures they cover more ground and patchy areas in the garden, it can also make them look very untidy and overgrown if they’re not trimmed properly
Yarrow can handle a garder shear if it’s already blooming. But the others should be pruned lightly in August to help restore shape and tidiness.
Woody Herbs?
Yes, even woody herb variations like sage, thyme, and lavender benefit from a light prune in late summer. It helps restore airflow around the plants and limits the chances of fungal disease spreading throughout the crop.
That being said, these herbs do not tolerate hard pruning well, so keep your hands gentle and only prune what you have to. NEVER cut into the old, woody stems. Unnecessary cuts and nicks will only weaken your herbs and lead to trouble down the road.
If you’re growing rosemary here’s exactly how I prune it to keep it productive. But, if you’re also growing lavender, this is how to prune it without hurting it.
Summer Shrubs That Flower On New Wood:
The rose of Sharon and certain hydrangea varieties (like panicle and smooth) are good examples of shrubs that flower on new wood and can handle a light tidy-up in August.
If you’re not sure which hydrangeas to prune now, this hydrangea pruning guide will help you do it right.
It may be a good idea to lightly cut these perennials back in late summer (August to early September),just don’t go overboard. Save the heavier pruning for when they’re fully dormant.
And for other shrubs that also need pruning in late summer or fall, here’s a full list you don’t want to miss.
What You Should Leave Alone In August!
Spring-Blooming Shrubs:
Spring-blooming shrubs such as lilacs, rhododendrons, and azaleas should only be trimmed after they’re done blooming in spring. The late summer pruning doesn’t make sense for them since it can potentially harm next year’s blooms.
Late-Season Flowering Perennials:
Asters, sedums, and goldenrods all fall into the late-season flowering category. These perennials will be actively blooming in the late season, so trimming them would just mean that you lose the beautiful flower display you’ve got.
Evergreens & Conifers:
Evergreen and conifer perennial varieties like boxwood, pine, arborvitae, or juniper benefit from late winter or early summer trimming. Pruning in late summer will just make them more sensitive to changing conditions.
Frost-Sensitive Plants:
While many perennials withstand cold with ease, there are some that are easily damaged by chilly weather and frost. If you cut them in late summer, they might regrow pretty quickly, but the new growth will be more susceptible to frost damage.
For example, think of tender plants like cannas or coleus. If you prune them now, they’ll push out fresh new growth that’s just too delicate to face the first frost.
It may serve you best to leave these perennials alone in August and wait till spring to trim them.
Let’s Conclude
Like I said, I’ve covered month-by-month pruning before, but this one’s all about keeping things simple, especially if you’re just starting out.
However, complexity and challenging gardening lingo are usually not taken well by beginners who’re just looking for simple and straightforward solutions/ideas. This article is for you folks!
One thing to take away from this: every plant is different!
While some plants rejuvenate and perk up after a good, hard prune in late summer, others might suffer and potentially lose next year’s blooms because the timing just didn’t sit well with them.
Embrace these differences and unique factors to bring life into your garden!
