7 Easy Ways to Manage Overgrown Perennials

By the end of a Georgia summer, even a well-kept perennials bed can look a little wild. Stems may be leaning into the walkway. Faded flowers can cover healthy foliage. Some plants may have grown together until you can hardly tell where one ends and another begins.

The good news is that most overgrown perennials don’t need to be removed. They may only need a little cleanup, thinning, dividing, or support.

Knowing what to do with overgrown perennials at the end of summer can improve the appearance of your flower beds without cutting away growth the plants still need.

Quick Answer: What Should You Do with Overgrown Perennials?

Start by identifying why the plants look overgrown.

You may need to:

• Remove dead or damaged stems
• Deadhead faded flowers
• Lightly trim floppy growth
• Add plant supports
• Divide crowded spring- or summer-blooming perennials
• Remove diseased foliage
• Wait until frost or early spring before completing a major cleanup

Don’t cut every perennial to the ground simply because the garden looks untidy. Some plants are still blooming, feeding pollinators, developing roots, or storing energy for next year.

1. Look at the Plant Before You Start Cutting

Before reaching for the pruners, take a closer look at each plant.

Ask yourself:

• Is the plant still flowering?
• Is the foliage green and healthy?
• Are the stems leaning but otherwise strong?
• Is the center of the plant thinning or dying?
• Are several plants competing for the same space?
• Do the leaves show signs of disease?

Healthy green foliage is still helping the plant produce and store energy. Unless it’s causing a serious problem, there’s usually no need to remove all of it at the end of summer.

A slow walk through the bed can save you from making cuts you’ll regret next spring.

UGA Extension’s guide to growing and maintaining herbaceous perennials

2. Deadhead Perennials That Are Still Blooming

Deadheading means removing faded flowers before they begin producing seed.

For some perennials, deadheading can encourage another flush of flowers. It also helps make a tired flower bed look cleaner without removing healthy foliage.

Good candidates may include:

• Coneflowers
• Coreopsis
• Garden phlox
• Shasta daisies
• Black-eyed Susans
• Salvia
• Bee balm

Cut each faded flower back to a healthy leaf, side shoot, or lower flower bud. Avoid leaving bare stems sticking several inches above the foliage.

UGA Extension recommends deadheading spent flowers during the summer to make room for additional blooms and keep perennial beds looking their best.

However, you don’t have to remove every seed head. Coneflowers, black-eyed Susans, blazing star, and other plants can provide food for birds and add winter interest.

Our Blazing Star plant guide explains why leaving some spent blooms can be helpful in a more natural or wildlife-friendly garden.

3. Remove Dead, Broken, or Diseased Growth

Dead and damaged stems can usually be removed whenever you find them.

Cut broken stems back to healthy growth or close to the base of the plant. Diseased foliage should also be removed, especially when leaves are heavily spotted, mildewed, or beginning to rot.

Place diseased material in the trash rather than adding it to a home compost pile. Then clean your pruning tools before moving to another plant.

Removing damaged material improves the appearance of the bed and may help keep certain problems from spreading.

A sharp pair of bypass pruners makes this work much easier. You can see several of the tools we regularly use in our guide to the best garden tools and supplies for beginners.

4. Lightly Trim Floppy Perennials

Some perennials become tall, stretched, or floppy by late summer. This often happens after heavy rain, strong wind, crowded growth, or insufficient sunlight.

A light trim may be enough to tidy them up.

Remove stems that are:

• Blocking a walkway
• Lying across nearby plants
• Broken or bent
• Smothering smaller perennials
• Resting against the ground

Try not to shear the entire plant into a tight ball. Instead, make selective cuts that preserve its natural shape.

Plants that are still flowering should only receive a light cleanup. A hard cutback can remove unopened flower buds and shorten the remaining bloom season.

5. Support Plants That Don’t Need Cutting

Sometimes an overgrown perennial doesn’t need to be pruned at all. It simply needs support.

Use a plant ring, bamboo stake, small section of fencing, or soft garden tie to lift stems away from nearby plants and walkways.

Support is especially useful for tall varieties of:

• Garden phlox
• Asters
• Coneflowers
• Peonies
• Dahlias
• Sedum
• Rudbeckia

Install the support carefully so you don’t damage the crown or roots. Avoid tying stems tightly together. Air should still be able to move through the plant.

Next spring, supports can be installed earlier while the plants are still short. The new growth will naturally hide them as the season continues.

6. Decide Whether the Perennials Need Dividing

An overgrown perennial may actually be overcrowded below the soil.

Signs that a plant may need dividing include:

• A bare or dead area in the center
• Fewer or smaller flowers
• Stems that continually fall outward
• Roots pushing above the soil
• The plant spreading into nearby plants
• A clump that has outgrown its space

UGA Extension notes that established perennial beds may benefit from periodic renovation because crowding creates competition for water, nutrients, and growing space. Dividing also improves spacing and air circulation.

As a general rule, divide spring- and summer-blooming perennials during fall. Divide fall-blooming plants in spring so you don’t interrupt their flower display.

Hostas, daylilies, iris, garden phlox, and many similar clumping plants can often be divided successfully.

For hostas, we normally prefer late winter or early spring. That timing makes the crowns easier to see and gives the divisions a fresh growing season to become established. You can also visit our Hosta plant guide for basic growing and seasonal care information.

7. How to Divide an Overgrown Perennial

Water the plant deeply the day before dividing it. Moist soil is easier to work, and hydrated roots handle transplanting better.

Then follow these steps:

1. Cut back excessive top growth if needed.
2. Dig around the outside of the clump.
3. Lift the plant carefully with a shovel or garden fork.
4. Shake or gently rinse away loose soil.
5. Pull the clump apart by hand or cut it with a clean knife or spade.
6. Keep sections with healthy roots and several strong growing points.
7. Discard weak, rotten, or diseased sections.
8. Replant the divisions at their original depth.
9. Water them thoroughly.
10. Add mulch while keeping it away from the crown.

UGA Extension recommends keeping newly separated divisions shaded and moist until they can be replanted. Healthy divisions generally need several vigorous shoots along with a good root system.

Don’t divide plants during the hottest part of the afternoon. A cool, cloudy day is much easier on both the plants and the gardener.

8. Don’t Divide Every Plant in Late Summer

Late summer in Georgia can still feel like the middle of July. Heat and dry soil can place extra stress on freshly divided plants.

Wait for cooler weather when possible. Spring- and summer-blooming perennials can often be divided after temperatures begin to moderate, provided they have enough time to establish roots before cold weather.

Avoid dividing:

• Plants that are currently blooming
• Newly planted perennials
• Drought-stressed plants
• Plants with severe disease or insect damage
• Fall-blooming perennials that are preparing to flower
• Plants that don’t respond well to disturbance

A plant may look overgrown but still be better left alone until spring.

9. Thin Aggressive Perennials Before They Take Over

Some perennials don’t politely remain where they were planted. They spread by runners, rhizomes, seedlings, or expanding clumps.

Remove unwanted growth around the outside of the planting. You can replant healthy pieces elsewhere, place them in containers, or share them with another gardener.

Be careful when moving named or patented varieties. Some patented plants cannot legally be propagated for resale.

Thinning aggressive plants helps protect slower-growing neighbors and keeps one variety from taking over the entire bed.

10. Refresh the Soil and Mulch

Once the plants have been cleaned up or divided, remove weeds and loosen the top layer of exposed soil.

A thin layer of compost can help improve the bed over time. Follow it with approximately 2 to 3 inches of mulch to hold moisture, moderate soil temperature, and reduce future weeds.

Keep mulch pulled back from the crowns and stems. Mulch piled directly over a perennial crown can hold too much moisture and contribute to rot.

UGA’s seasonal garden guidance also recommends checking mulch levels and keeping mulch away from perennial crowns.

For another easy way to improve your beds, read Can You Use Fallen Leaves as Mulch in Flower Beds? once it has been published and add its final link here.

What We See at Our Plant Farm

At Bobby & Lynn’s Plant Farm, we often see perennials look their roughest near the end of summer.

Georgia heat, humidity, heavy rain, and fast growth can leave plants leaning, tangled, or crowded. That doesn’t always mean something is wrong.

Many plants simply need selective cleanup rather than a hard cutback.

We start with the obvious problems. Dead stems come out. Diseased leaves are removed. Plants covering walkways or smothering their neighbors are trimmed or supported.

Crowded clumps are evaluated separately. When division is needed, we consider the plant’s bloom time, the weather, and whether the roots will have enough time to settle before winter.

The biggest mistake is treating every perennial the same. Some plants benefit from fall division. Others are better divided in spring. A few should be disturbed as little as possible.

Should You Cut Overgrown Perennials to the Ground?

Not necessarily.

Cut a perennial to the ground at the end of summer only when:

• The foliage is completely dead
• Disease is severe
• The plant has finished its seasonal growth
• The stems are broken beyond repair
• The specific plant is known to respond well to an early cutback

Otherwise, leave healthy green foliage in place.

Many gardeners wait until frost naturally kills the foliage. Others leave sturdy stems and seed heads through winter to provide food, shelter, and visual interest.

The right choice depends on the plant and the style of garden you want.

Quick End-of-Summer Perennial Checklist

Before calling the bed finished, check the following:

• Dead flowers have been removed where appropriate
• Healthy seed heads have been left for birds
• Diseased foliage has been discarded
• Broken stems have been cut out
• Floppy plants have been supported
• Aggressive plants have been thinned
• Crowded spring- and summer-blooming plants have been evaluated for division
• Fall-blooming plants have been left alone
• New divisions have been watered deeply
• Mulch has been pulled away from plant crowns

Frequently Asked Questions

Can I cut back all my perennials in August?

It’s usually better not to cut everything back at once. Many perennials are still growing or flowering in August. Remove dead material and make selective cuts, but leave healthy foliage unless the plant has finished its season.

Is late summer too early to divide perennials?

It can be too early when the weather is extremely hot or dry. Wait until temperatures begin to cool, then divide suitable spring- and summer-blooming perennials. Keep new divisions watered while they establish.

What should I do with perennials that are falling over?

Remove broken stems first. Then use stakes or plant supports to lift healthy growth. If the plant continually falls outward and has a bare center, it may be overcrowded and ready for division.

Should I fertilize after cutting back perennials?

Avoid pushing tender new growth late in the season with heavy fertilizer. Compost and proper watering are usually more helpful. A soil test can tell you whether the bed actually needs additional nutrients.

Can I move an overgrown perennial instead of dividing it?

Yes. A healthy perennial can often be lifted and relocated. However, a very large or crowded clump may establish more easily when divided into smaller sections.

Final Thoughts

Figuring out what to do with overgrown perennials at the end of summer doesn’t have to turn into an all-day garden overhaul.

Start small. Remove dead growth, clean up faded flowers, support leaning stems, and give crowded plants a little breathing room. Divide only the plants that need it and only when the timing is right.

Your flower bed may still look a little relaxed and natural—and that’s perfectly fine. By late summer in Georgia, most of us are looking a little tired too.

A thoughtful cleanup now will make the garden easier to manage this fall and give your perennials a healthier start next spring.