I’ve got to admit, I have a laissez-faire attitude when it comes to gardening.
Most of the plants in my garden were picked up as throwaways from job sites or rescued from the clearance rack at a garden center.
But even though I trust that the plants in my garden know what they’re doing, I have got to prune back my perennials.
Part of that reasoning is selfish; I genuinely love crawling around in the mulch and soil with my pruners and soil knife, snipping back perennials and investigating for new growth and funky critters. This is my own little tip for getting kids into the garden, but you can read more in our guide to gardening with children.
Another more pragmatic reason for pruning back these beauties is very simple: it’s healthy for the plants. Leaving around dead or dying foliage is bad news for our garden treasures. We might as well put up a sign inviting fungi and disease to move right into our gardens.
Some perennials benefit largely from regular pruning during the summer growing season, but the most important cleanups are in the fall and the spring.
A host of perennials respond best to a tidy spring cleaning and are seemingly rejuvenated from the practice. Other perennials favor a quick cutting-back before winter sets in, so that they can get right down to business in the spring, unimpeded by last year’s growth.
The trick to doing this the right way is to know when to cut what – and that’s what we at Gardener’s Path have prepared for you to read today. A healthy guide to what to cut back in the spring and in the fall follows here, so bookmark this page and revisit it when you need to reference it!
Perennial Pruning Tips
There are some basics you should read up on before jumping into pruning. One of these is the Gardener’s Path Guide to Pruning Basics. For most perennials, you want to have a good pair of sharp hand pruners, or a pair of shears.
There are a few things you’ll see below that may strike you as odd. Let’s go over them:
Plants that produce a bazillion seeds are eager to multiply in your garden without the courtesy of an invitation. For some plants this can be desirable, but other plants tend to become aggressive growers, invading areas of the garden where they aren’t welcome.
Leaving certain seed heads attached for too long increases your odds of finding new patches of your favorite self-seeding plants.
We aren’t talking about that favorite of the herb garden here! Instead, “basal growth” refers to the leaves, shoots, and stems that start growing from the very base of the plant.
Some perennial cutback advice suggests “pruning back to the basal growth,” which simply means leaving a few inches of last year’s growth standing when you cut back the perennial.
Composting is a highly desirable skill and practice for gardeners.
However, when it comes to cutting back perennials, it is best to dispose of the old growth you’ve removed from the plant rather than composting it. This old foliage can harbor fungal problems and disease and is best to destroy, rather than trying to compost it and possibly contaminating your compost.
A hard frost is one of the earliest signs of fall, and a final goodbye from winter.
Four or more hours of below-freezing temperatures qualifies as a “hard” frost. It usually causes most perennial plants, annuals, and vegetables to die back to their roots.
It can be difficult to pinpoint when the last hard frost will take place, but pay close attention to the weather forecast – and remember that patience is the gardener’s best friend.
While you’re planning for local frosts, consider reviewing our Spring Garden Checklist!
A handful of tools can also make perennial cutbacks a far more pleasant task:
Your trusty garden pruners are a great option, along with a pair of finer snips.
A soil knife can be an indispensable tool when it’s needed.
A spray bottle filled with straight rubbing alcohol functions as a handy and quick sterilizing spray when pruning, helping to prevent the spread of disease and fungal infections.
Some people enjoy using knee pads when they’re toiling in the soil, but they aren’t necessary.
Be prepared with something that’s durable enough to carry and transport the cutback perennial foliage, because it will add up quickly! A large bucket or a tarp are ideal, or you could try a large basket or wheelbarrow.
When the autumnal equinox rolls around, it’s time to tend to the following plants:
Bearded Iris (Iris germanica)
If fungal growth had a haven, it would be the leaves of an iris.
Also known as German iris, cut these back in the fall to minimize fungal problems and garden pests.
A contestant in the running for “Most Possible Mildew on a Perennial” (an award that no one wants to win) is beebalm, aka horsemint.
Wait until fall, and then cut these to the ground.
Blanket Flower (Gaillardia)
One of my personal favorite perennials, blanket flowers are easy to prep for winter.
If you like a tidy garden, cut back the flower stalks in late fall. But if you don’t mind their presence in the garden, you can leave them until next year.
Blanket flowers are sensitive to soggy soils, so avoid mulching them over the winter.
Bronze Fennel (Foeniculm vulgare)
A favorite meal of swallowtail caterpillars, bronze fennel is becoming an increasingly popular addition to gardens. Just watch out for that prolific self-seeding!
Cut these guys back to the ground in the fall.
I’ve got a love-hate relationship with catmint. It’s a fantastic plant for adding cool hues to an area, so long as you have a LOT of area for it take over. Luckily, catmint can be pruned back heavily any time of the year.
In the fall, you can cut these back to as low as a few inches from the ground, but you’ll have a hole in your garden until they flush back in the spring.
More modest cuts of about half the height of the plant during the fall are recommended if catmint is a foundation of your perennial border, coupled with regular summertime pruning.
The flowers of columbine remind me of futuristic spaceships, and that’s cool… But their ceaseless self-seeding is not so cool in contained areas.
Pruning columbine flowers and seedpods back in the fall helps to prevent self-seeding. Otherwise, it is recommended to leave the foliage of the plant to overwinter as is.
I’ve always been a fan of the native daylily, even with its not-so-affectionate name “ditch lily.”
If you leave the foliage on these plants to overwinter, they’ll offer you an unattractive but free mulch. If you want to plan ahead for an easier springtime, cut back the foliage of the daylily in the fall to save yourself a headache in the future.
Japanese Anemone (Anemone hupehensis)
You can leave the fall-blooming anemone standing over the winter, but if the foliage and stems turn black after frosts they should be cut to the ground.
Another victim of “too much fungus!” the peony is a gorgeous bloomer that leaves an often unpleasant heap of fall foliage.
Most gardeners are chomping at the bit, ready to prune these guys back at the first moment. Wait until the first hard frost, then cut the leaves back to the ground.
Woody salvia should be cut back regularly throughout the season by removing spent flowers, and does best when it receives a heavy fall pruning, reducing the size of the plant by about half.
A beautiful plant to have in any garden, veronica is an easygoing perennial that requires minimal care.
After the first hard frost, cut veronica (aka speedwell or gypsyweed) back to a few inches above the ground. It’ll bounce back happy as a clam in the spring.
Yarrow (Achillea millefolium)
A favorite and necessary addition to any meadow-like border, yarrow offers a unique flower shape and some interesting foliage.
These respond very well to fall pruning, cutting the plant back to the basal leaves.
With the arrival of spring, these are the plants that you want to add to your pruning list:
Amsonia (Amsonia hubrichtii)
Amsonia, also known as blue star, prefers to be thrown into a high-sun environment where it can go wild growing.
Leave these standing over the winter to add some interest to the garden and encourage self-seeding.
Another icon of meadows and roadsides in the country, aster is a tough plant that wants to be left alone over the winter.
Allow it to enjoy the snow and the cold while adding some cold-season interest to the garden. For whatever reason, aster thrives on being left alone over the winter.
I would have voted for astilbe if it ran for president. Delicate and pleasantly-colored foliage pairs with spires of colorful flowers. Better yet, it’s a plant that requires minimal care and maintenance.
The old foliage helps protect the plant from winter damage and requires minimal cleanup in the spring.
Balloon Flower (Platycodon grandiflorus)
Beautifully hued and delicate flowers adorn these beauties.
Balloon flowers grow well in clumps, and are eager to self-seed. This means that it’s best to leave balloon flowers standing throughout the winter. They also add some interesting winter form to your garden!
Black Eyed Susan (Rudbeckia hirta)
If you have somebody close their eyes and imagine the first flower that comes to mind, chances are that it’s a black eyed susan. Wonderfully reliable and eager to take root in many places, black eyed susans are also vigorous self-seeders.
If you leave them standing in the winter they’ll offer a food source to birds. Clean up the debris in the springtime.
Butterfly Bush (Buddleja)
An icon in the garden, butterfly bushes offer a wild growth habit highlighted with brightly colored conical flowers.
Leave these standing over the winter, and watch for the first signs of new growth popping out before cutting this vigorous plant back to a height of about one foot in the spring.
The image here was taken on August 16th, and the plant itself was cut back on March 15th. That’s a lot of growth!
Although there are a tremendous variety of coneflowers out there, most of these hybrids seem to revert or reseed back to their true purple color. That’s no problem, because these long-lasting flowers are vital food sources for various types of of wildlife over the winter months.
Leave them standing and enjoy their snow-capped flower heads being pecked apart by eager birds in need of a meal.
Coral Bells (Heuchera)
Coral bells are a great companion to many perennial plants and can even stand on their own in the interest department. However, they are prone to ground heaving, when the frost pushes a plant up and above the surface.
Leave the foliage intact on coral bells to guarantee an extra level of protection from the cold.
A perennial tolerant of just about any harsh conditions you can throw at it, coreopsis is one tough plant.
Leave the flowers and foliage intact over the winter. Also commonly known as calliopsis and tickseed, coreopsis prefers being undisturbed until springtime.
The icon of summertime, it’s important to recognize the difference between Montauk daisies and Shasta daisies.
Montauk daisies (Nipponanthemum nipponicum), which genreally open later in the year, should be treated more like a woody shrub than a perennial. Leave them alone over the winter and only cut back dead stems.
Shasta daisies (Leucanthemum × superbum), on the other hand, respond better to being left alone over the winter, and then having last year’s growth removed in early spring.
Dianthus barbatus or Sweet William is a common variety.
You can usually leave this softly-hued perennial in place during the winter. These don’t produce much in the way of foliage or mess, and will only require a quick and light cleanup in the spring.
Certainly one of the more dramatic entries in the garden, gardeners will often cut back the flower stalk of a foxglove after it finishes blooming.
The rest of the plant can be ignored until springtime, when a quick touch-up cleaning is all that’s required.
Gaura (Oenothera lindheimeri)
Lovely flowers on spindly growth are an attractive element in the garden, but gaura is hardly a long-lived perennial.
Also known as Lindheimer’s clockweed, Lindheimer’s beeblossom, or Indian feather, the best chance to have these make a return appearance next year is to leave them undisturbed over the winter, so that they may self-seed.
Cut liatris (aka blazing star or gayfeather) back to the ground in the winter.
Most of these have difficulty reflowering, or simply won’t, so leaving the seedheads attached during the early stages of the cold season allows the seeds to disperse and replenish the plant next year.
Probably the most well-known plant to have in the garden, these are sometimes referred to as plantain lilies or giboshi. Hosta is a vigorous and incredibly hardy perennial. I’ve dug them up and divided them in July, then sipped a cool mojito and admired their blooms in August.
Still, hosta prefers to have its leaves left alone over the winter, to serve as a mulch for the roots. Remove the old, shriveled material in the spring to make room for new growth.
Joe Pye Weed (Eutrochium)
Let’s be honest – if a plant has the word “weed” in its name, it probably doesn’t require much care.
Lucky for us, Joe Pye weed is also an eager self-seeder, and offers lovely foliage that is beloved by local wildlife.
You can let Joe Pye weed stand throughout the winter and cut it back in the spring… or you could leave it standing. Joe Pye don’t care!
Lamb’s Ear (Stachys byzantina)
Watch out for those spiky flower stalks on this silver-hued, low-growing perennial! Lamb’s ear is just as easygoing in the winter as it is the rest of the year.
You can completely ignore it over the winter, and give it a quick cleanup in the springtime.
Like a handful of other perennials on this list, lavender is more sensitive to soggy soil than it is to the winter cold.
To ensure that this fragrant staple in that sunny corner of your yard makes it back next year, wait to prune it until after the last hard frost, to protect new growth that is particularly sensitive to the cold.
Mugwort (Artemisia vulgaris)
These guys remind me of Dusty Miller, and for that their soft-hued, blue-green foliage is welcome in my garden!
Leave it standing throughout the winter and cut it back in the springtime.
I have a lot of experience planting plumbago, but that’s because it has a difficult time making it through the winters, and because it seems to disappear in the spring! It sometimes goes by the common name leadwort.
The only trick I’ve found to knowing exactly where my plumbago will appear again is to leave the old foliage attached throughout the winter.
Russian Sage (Perovskia atriplicifolia)
After coming up with a plant list for this guide, I’ve realized how much I love the silvery-blue-hued perennials, and russian sage is at the top of that list.
If you have room to let this guy grow, it will provide a beautiful and reliable wall of blue.
Like lavender, the new growth is sensitive and does not react well to winter cold. Wait to cut back until after the last hard frost, or when you see new growth starting in the spring.
“Hey, you said to cut these back in the fall!” You are correct, attentive reader – but fall cutbacks are for the woody salvia.
The softer-stemmed salvias that thrive in warmer climates prefer to be cut back in the spring, because their new growth is sensitive to cold.
Unsure of which type of salvia you have? Take a picture and let us know on the Gardener’s Path Facebook page!
With a tough common name like “stonecrop,” it’s no wonder that these guys like to be left alone in the winter. Lucky for us, they offer some winter interest in the garden.
Sedum is one of the first plants to push out new growth in the spring, so when you see those new rosettes forming, you’ll know spring has sprung.
Until Next Time…
And there you have it, a handy guide to perennial cutbacks that you can refer to whenever it’s needed.
Have something in your garden that’s not listed this guide? Let us know in the comments, and we’ll help you out!
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Photos by Matt Suwak, © Ask the Experts, LLC. ALL RIGHTS RESERVED. See our TOS for more details. Liatris photo used with permission. Uncredited photos: Shutterstock.
About Matt Suwak
Matt Suwak was reared by the bear and the bobcat and the coyote of rural Pennsylvania. This upbringing keeps him permanently affixed to the outdoors where most of his personal time is invested in gardening, bird watching, and hiking. He presently resides in Philadelphia and works under the sun as a landscaper and gardener, and by moonlight as a writer. An incessant questioning of “Why?” affords him countless opportunities to ponder the (in)significance of the great and the small. He considers folksy adages priceless treasures and is fueled almost entirely by beer and hot sauce.