Which side are you on when it comes to cutting back asters? Our guide will help you to pick
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To cut back asters in the fall or wait for spring – that is the question. Gardeners often prefer one method to the other when it comes to when to cut back asters. If you are yet to commit fully to one stance or are new to growing asters and looking for guidance, we are here to help you decide.
Asters are one of the best perennials for providing blooms in late summer and early fall. Their daisy-like flowers are adored by gardeners and pollinators alike and there is a wide selection of native North American plants or European aster varieties to choose from for any backyard ideas.
After a stunning display, asters naturally die back for winter. There are potential benefits to both timings for cutting back asters. When you wonder if you should cut back asters in the fall, our guide gives a clear picture of the options available and why you may favor either method.
Asters are classic fall-blooming perennials that provide a welcomed burst of color just as many other flowers are fading. Native to North America, these hardy plants reward gardeners with abundant daisy-like blooms well into autumn. But to keep asters looking their best year after year, it’s crucial to know the optimal timing and proper techniques for cutting them back in the fall.
Why Cut Back Asters in the Fall?
There are several key reasons to cut back asters in the fall
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Removes faded, dying flowers that can harbor pests and diseases if left on the plants.
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Eliminates places where some damaging insects can overwinter
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Prevents self-seeding in areas where asters spread aggressively.
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Removes top growth that is vulnerable to winter damage from wind, cold temperatures, snow and ice.
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Encourages fresh, healthy new growth to emerge from the base in spring.
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Allows better air circulation around plants to reduce foliage diseases.
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Gives the garden a tidy, cared-for appearance going into winter.
When is the Best Time to Cut Back Asters?
To maximize health and flowering, asters should be cut back:
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After they have completed blooming for the season, usually in late fall.
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Once several hard frosts or freezes have caused the foliage to die back and look spent.
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Before the first snowfall, typically late fall to early winter.
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Around the time of the first hard frost, but delay if plants are still actively flowering.
The goal is to time it late enough so asters won’t try to regrow or rebloom, but early enough to tidy them before heavy snows or freezing temperatures arrive.
How Far Back Should You Cut Asters?
When cutting asters back in the fall, prune most types down quite close to the ground for best results. The optimal cutting height is:
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2 to 3 inches above the soil surface.
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Remove spent flower stalks and dead leaves down to the basal growth or ground level.
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Cutting lower minimizes overwintering spots for some pests and diseases.
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But avoid pruning lower than 2 inches above soil to prevent damaging the crown.
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Leaving low basal foliage intact allows fresh stems and leaves to emerge quickly in spring.
The Best Tools for Cutting Back Asters
To efficiently prune overgrown asters, use these recommended tools:
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Bypass pruners – Makes clean cuts on individual stems up to about 1⁄2 inch diameter.
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Garden shears – Quickly cut back many larger or thicker stems at once.
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Hedge shears – Allow fast pruning of very wide swaths or plantings.
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Loppers – Extend your reach to the centers of big plants.
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Chainsaw – Only necessary for extremely overgrown, woody asters.
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Be sure to sanitize tools before and after use to prevent spreading diseases. Pruning saws work well on thicker wood.
Step-by-Step Guide to Cutting Back Asters
Follow this simple procedure for properly pruning asters in the fall:
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Wait until several hard frosts have passed and plants look completely dormant and spent.
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Clear away fallen leaves and debris around the base of the plants first.
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Cut off dead or damaged growth down to healthy live stems.
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Prune back spent flower stalks to the lowest foliage or live growth.
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Shear back remaining leaves and stems to 2-3 inches above the ground.
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Rake up and dispose of the cut foliage debris when finished.
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Apply 2-4 inches of shredded bark or leaves as winter mulch around freshly cut plants.
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Clean and disinfect your tools after use.
What to Do With the Trimmings
Once finished cutting back your asters, you’ll likely have a large pile of plant debris leftover. Here are some smart ways to handle the trimmings:
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Compost the plant waste to create nutrient-rich organic matter for garden beds. Just ensure no diseases were present.
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Use the pruned foliage as browns in your compost pile.
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Lay clippings as winter mulch around other plants to protect from cold weather.
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Bag up the debris and set it out for yard waste collection if available in your area.
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Destroy any diseased plant material to avoid spreading problems to other plants.
Avoid Cutting Asters Too Early
It’s vital not to cut back asters prematurely in fall before they have gone fully dormant:
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Pruning while still actively growing can cause unattractive late season regrowth.
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Cutting too early may reduce next year’s flowers.
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Always wait until well past flowering and several hard frosts or freezes occur.
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Delay cutting if warm spells trigger new growth or intermittent reblooming.
Give those tenacious late season blooms a chance to flourish before cutting plants back!
Optional Reasons to Leave Asters Uncut in Fall
Some situations when you may choose to forego cutting back asters in fall include:
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If fall remains unusually warm with little frost or freezing.
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When plants are still actively growing and flowering into winter.
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In warmer climates where winter weather won’t damage tender growth.
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To provide seed heads for birds and visual interest through winter.
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To allow self-seeding in appropriate areas.
But for most gardeners, following best practices for fall cutting will produce the healthiest, most prolific plants.
Benefits of Proper Fall Cutting Back
Here are some of the top advantages of cutting asters at the right time each autumn:
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Promotes compact, bushy basal growth the following spring.
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Removes insect eggs and disease spores that may overwinter on old foliage.
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Gives the garden a tidy, cared-for appearance going into winter.
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Reduces the need to stake floppy growth the following year.
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Minimizes overwintering sites for some damaging pests.
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Allows better air circulation and light penetration at soil level.
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Encourages prolific flowering on vigorous new stems.
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Boosts winter survival and cold hardiness.
Ongoing Fall and Winter Aster Care
Continue properly caring for your asters after fall cutting with these tips:
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Apply 2-4 inches of shredded leaves or bark as winter mulch around the base.
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Water whenever soil dries out if winter stays mild.
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Place evergreen boughs over crowns for extra insulation in very cold regions.
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Loosely cover with row cover fabric to protect from heavy snow or ice.
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Spray with an anti-desiccant leaf sealant before extreme cold hits.
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Remove mulch and coverings next spring after all danger of frost has passed.
FAQs About Cutting Back Asters
Here are answers to some commonly asked questions:
How short can I cut back asters in fall?
Leaving 2-3 inches of growth is safest to avoid harming the crown and next year’s buds.
Is fall pruning of asters recommended?
Yes, cutting them back in late fall allows you to tidy up the garden once flowering finishes.
Do I need to cut asters back every autumn?
Annual fall pruning is best to maintain vigor, maximize blooming, and improve shape.
What is the best way to care for asters in winter?
After fall cut back, mulch the base to insulate roots. Leave some stems and foliage intact too.
Will asters come back reliably every year?
Most are hardy perennials that will return each spring and re-bloom in suitable growing conditions.
With proper timing and technique, fall is the optimal season for cutting back asters. Prune when plants are dormant after a hard frost for best results. Proper fall cut back keeps asters flowering abundantly season after season.
Can asters be Chelsea chopped?
‘The Chelsea Chop’ is a phrase commonly used to describe cutting back perennials to coincide with the RHS Chelsea Flower Show. Cutting back perennials in late May or early June can promote bushier and more upright plants that flower profusely. Asters are a perennial to cut back in June, especially taller varieties that can get leggy and start to flop later in the season. Chopping them back by up to a half promotes lots of side shoots to carry flowers and removes the need to stake plants.
If and when you cut back asters in spring, it can also be an ideal time to divide plants. Clumps of asters will expand over the years, they may get too big for their space and their vigor may decline after 3-5 years. Knowing how to divide plants allows you to easily split the clumps to get more asters and rejuvenate older clumps to keep them performing for years to come.
The reasons to cut back asters in the fall
Cutting back asters keeps clumps healthy ( credit: Getty s / Jacky Parker Photography)
Asters bloom profusely throughout late summer and early fall, bringing abundant color to any flower bed ideas. Asters benefit from regular deadheading throughout the summer to prolong their flowering display, but the plants will start to fade as the temperatures drop at the end of the season. The foliage dies back and those once-colorful blooms transform into brown seed heads, that become tufty as they mature.
Gardeners who strive for a neat and manicured backyard will add cutting back asters to their fall gardening checklist, as trimming perennial plants before winter tidies up the flower bed and removes straggly foliage or plant debris.
Unless you have meticulously deadheaded all the spent blooms throughout the season, you may have quite a few old flowerheads remaining on the plant. Asters are self-seeding flowers that can spread around the yard. Therefore, cutting back in the fall can prevent the plant from dispersing seeds around the garden.
Disease prevention is another reason to cut back asters in the fall. Kiersten Rankel, a plant expert from the Greg app, explains removing existing diseased foliage ‘prevents issues from persisting through winter’ and cutting back in fall may be beneficial in certain areas.
‘If you live in an area with high humidity or where fungal diseases are common, its often better to cut asters back in the fall,’ says Kiersten. ‘Trimming them down to about 6-8 inches above the ground after the first frost can help prevent disease issues and keep your garden looking tidy. This also makes spring clean-up a bit easier.’
Removing old plant debris around the garden can prevent pathogens or pests from sheltering and overwintering in old foliage or stems and causing problems when they reappear in spring. The likes of leafhoppers and caterpillars are aster pests that can overwinter in old stems and foliage around previously infested plants.
Kiersten Rankel is a certified Louisiana Master Naturalist and regularly volunteers with local community gardens and non-profits to help restore critical ecosystems along the Gulf Coast. She earned her masters degree from Tulane University in Ecology and Evolutionary Biology after her undergraduate degree in Environmental Biology, also from Tulane.