My mom had this sort of “gardening tradition” where she and I would prune the backyard flowers in the month of August and have a refreshing sweet treat as a reward right after.
I never asked what the point of pruning in August was because I was too young at the time, but now that I’m into gardening myself, I feel like pruning in August is special in every way!
In this article, I’ll be taking you through a list of perennials you can cut back in August to achieve a neater, more vibrant garden in no time. And, like always, I’ll make sure to sprinkle in some tips and words of wisdom here and there!
Yes, You Should Cut Back Some Perennials In August!
Pruning in August can actually prove to be beneficial for your perennials.
Since most perennials grow unevenly and in irregular shapes and sizes, pruning can make them look a lot neater and more aesthetically pleasing.
If your perennials are aggressive, self-seeding spreaders, pruning can bring them under control and help contain unwanted spreading. Many perennials even start reblooming after a good, hard prune!
Not sure what to cut and what to leave alone? This quick August pruning guide walks you through exactly that.
But First…How To Know When A Perennial Needs Cutting Back?
Well, since the plant won’t directly converse with you, there are some indicators you need to look out for in order to figure out whether or not cutting back is necessary. Some clear visible indicators include:
Perennials To Cut Back In August
1: Catmint (Nepeta)
Cut back your catmint after the first flush of blooms begins to fade. Doing so will not only promote even growth and neatness, but also possibly another flush of vibrant blooms.
2: Salvia (Salvia Nemorosa Or S. Greggii)
Cut back your salvia plants by one-third in August. Spent flower spikes create unnecessary stress and burden for the perennial; therefore, removing them is ideal.
August pruning should result in bushier, healthier-looking salvias in no time.
August pruning should result in bushier, healthier-looking salvias in no time. Here’s how I keep mine blooming strong all summer long.
3: Shasta Daisy (Leucanthemum)
For Shasta daisies, you want to remove all spent flower stalks and discolored foliage early in August. Because this perennial is aggressive when it comes to self-seeding and spreading, regular pruning can help keep it in check and even encourage a short-lived reblooming effect.
4: Yarrow (Achillea)
Yarrows are typically resilient and can withstand a hard prune without any problem whatsoever.
Feel free to cut these back to basal foliage in August and enjoy a new flush of blooms if you’re in a milder region (zones 6 and up). I definitely wouldn’t recommend doing this in cooler zones!
5: Coreopsis
Coreopsis should simply be cut back hard whenever they display signs of stagnation. These perennials bloom rapidly after pruning and are super low-maintenance, meaning they’re perfect for beginners.
6: Garden Phlox (Phlox Paniculata)
Because garden phlox bloom in clusters, you’ll need to deadhead entire clusters in August and trim any weak, degrading stems to lighten up this spreading perennial.
The removal of brittle stems and structure allows for better airflow and can limit the risk of fungal diseases, which garden phlox are often quite susceptible to.
7: Daylilies (Hemerocallis)
Pruning daylilies in August can help limit the formation of seed pods that lead to aggressive spreading in the garden. It may also be a good idea to divide your daylilies around this time if they appear to be crowded.
Some varieties are known to bloom more than once if cared for properly, this is how I get repeat blooms from my daylilies every year.
8: Bee Balm (Monarda)
Although light pruning works, I personally prefer to cut back my bee balms to the base, which rejuvenates them and encourages them to bloom even better every time.
Also, it helps reduce the risk of powdery mildew, which you might have noticed already that this plant is notorious for (especially in humid late-summer conditions).
In some cases, a good, hard prune can also trigger a short rebloom, if conditions are right.
9: Blanket Flower (Gaillardia)
When it comes to blanket flowers, they generally don’t need much love and attention. Some hard pruning in August (cutting back by one-third ideally), with consistent watering and fertilization, is enough to keep them coming, even if it’s for a short period every time.
And while you’re out tidying up the garden, it’s also a great time to plant for next year. Here are 10 flowers you can sow in August for gorgeous spring blooms.
Let’s Conclude
While not all perennials react well to being cut back in August, there are some that actually prefer it and, for them, there’s no better reblooming catalyst than this.
Though pruning is a lot of work sometimes, it does eventually pay off. Patience and forward-looking vision are key!
I have two hibiscus and a lantana plants in pots that have gotten to large for me to pick up and store on the back porch. I would like to root a part of them to keep for next year. Any suggestions?
Hi Doris! 😊 That’s a great idea, both hibiscus and lantana root pretty easily from cuttings!
I’d take 4–6 inch softwood cuttings (non-woody stems), remove the lower leaves, and stick them in moist potting mix. I usually dip the ends in rooting hormone to speed things up, then keeps them in a bright, warm spot out of direct sun. Mist them lightly and cover with a plastic bag to hold humidity. You’ll likely have baby plants in a few weeks!
Can I cut back sedum at any time
Hi Yvonne! 😊 You can! I usually pinch or cut mine back in early summer to keep them from flopping, it makes them bushier too. But if it’s late in the season, I let the blooms finish and just clean them up in fall or early spring. 😊