Fall is arriving fast – and that means it’s time to take a look at many of the perennials growing in your flowerbeds to see if it’s time to divide them!
One of the best things about growing perennials is how they come back year after year, growing a little larger each season. But as those years pass, many begin to get overcrowded. The roots grow so thick that the plant struggles to bloom. Even worse, the center of the plant begins to die back while the edges continue to spread.
That is exactly when dividing becomes important. And as it turns out – fall just happens to be one of the best times of all to get the job done!
6 Perennials You Need To Divide In The Fall
Why Fall Is The Perfect Time To Divide
When autumn arrives, it’s easy to see which plants have grown too big for their space. Unlike spring, when growth is just starting, fall lets you see the full size of your perennials at their peak. That makes it clear which ones need to be split and replanted.
Dividing in the fall also gives the roots plenty of time to settle in before winter sets in. By the time spring rolls around, your divisions are ready to burst out of the soil with strong new growth.
Not all perennials need dividing every few years, but many of the most popular ones do. Some benefit from it to keep blooming strong, while others simply grow so quickly that splitting them is the only way to keep them from taking over the garden.
Here is a look at six of the best perennials to divide in the fall, along with a simple look at how to handle each one!
1. Hostas
Hostas are one of the most common perennials in shade gardens. They grow into large, lush clumps of foliage that fill shady spaces with beautiful leaves. But because hostas expand steadily each year, they can quickly outgrow the area where they were planted.
The best time to divide hostas is in early fall, once the heat of summer has passed. Start by digging up the entire clump with a sharp spade. Work in a circle around the plant to get as much root as possible. Once lifted, you can either pull apart the clump by hand or cut it into sections with a knife or shovel.
Each division should have several healthy shoots and roots attached. Replant the divisions right away, spacing them far enough apart so they have room to grow for years to come. Water them deeply, and by spring, they will be ready to thrive again.
2. Daylilies
Daylilies are known for their tough nature and their ability to bloom with little care. But over time, the clumps become so dense that the number of flowers actually starts to drop. Dividing perennial daylilies in the fall will help keep them blooming strong. It also gives you a way to create more plants for your landscape for free.
To divide daylilies, cut back the leaves to about six inches tall so you can easily see the crown of the plant. Dig up the clump and shake or rinse off the soil to expose the roots.
You can usually pull apart the clump into smaller sections with your hands. If the roots are thick and tight, this is where a garden knife is perfect for doing the job. Each piece should have both roots and leaves attached. Affiliate Link: Hori Hori Garden Knife
Replant the divisions right away in soil enriched with compost, and water them well to help the roots re-establish.
3. Black-Eyed Susan
There is little doubt that black-eyed Susan (pictured at the top of the article) brings bold late-summer and fall color to flowerbeds. But they are fast spreaders. If left alone for too long, they can take over an area. Dividing them every few years in fall keeps them manageable and helps them continue to bloom with energy.
Begin by digging up the clump in early to mid-fall. The roots of black-eyed Susan are usually easy to work with, so you can often separate them by pulling the clump apart with your hands. If the center of the plant looks weak or has stopped producing flowers, discard that section and keep the strong outer pieces.
Divide and replant the perennials in the fall where you want them, spacing them to allow good airflow and room to grow. Within a season, they will be back to filling the garden with their bright golden blooms.
4. Coneflower
Coneflowers are another hardy perennial that benefit from division in the fall. These plants often develop crowded centers that lose vigor after a few years. Splitting them gives the roots more room and restores their ability to produce strong blooms.
To divide coneflowers, cut back the stems to a few inches above the ground after flowering has ended. Use a spade to carefully lift the root clump out of the soil. Once it’s out, cut or pull the clump into several smaller sections.
As with black-eyed Susan, discard any weak or woody centers and keep the healthiest pieces. Plant the divisions back into the soil at the same depth they were before, and water them in well. By the following summer, the new clumps will be blooming with their classic purple, pink, or white flowers again. For more on coneflower, see our article: What To Do When Coneflower Plants Finish Blooming!
5. Creeping Phlox
Creeping phlox is a low-growing perennial that creates a carpet of color each spring. While it looks beautiful spreading across a slope or rock garden, it can become too thick or even die out in the center if not divided every few years. Dividing this perennial in fall keeps creeping phlox healthy and helps it continue to spread evenly.
To divide creeping phlox, gently dig up sections of the mat-like plant. Unlike taller perennials, creeping phlox has shallow roots, so you don’t need to dig deep. Look for strong, healthy portions on the edges of the clump and separate them from the older middle.
Replant these divisions right away, setting them just slightly below the soil line and pressing the soil back in firmly. Give them a good watering, and by spring, they will root in and spread quickly, producing another flush of colorful blooms.
6. Why Fall Is The Perfect Time To Divide Peonies
Peonies are long-living perennials that can stay in place for decades, but after many years, they may become overcrowded or stop blooming. Dividing peonies is not needed as often as some other perennials, but when it is, fall is the best time to do it.
Dividing peonies takes a bit more care because their roots are thick and tuber-like. Start by cutting back the foliage to ground level in early fall. Dig up the clump carefully, lifting as much of the root system as possible. Wash the roots off with water so you can see the eyes, which are the small pink or red buds that will grow into next year’s stems.
Use a sharp garden knife to cut the clump into sections, making sure each piece has at least three to five eyes and a good amount of roots. Replant them at the same depth they were growing before. Planting too deep can prevent blooming. With time, your peony divisions will grow into full, flowering plants that can last for generations.
Why Fall Division Matters
Dividing perennials in the fall is more than just a way to control size. It’s a method to keep your garden healthy and full of life. When you split perennials in Autumn, you are working with cooler weather that is easier on both plants and gardeners.
The soil is still warm enough for roots to grow, but the hot, drying sun of summer is no longer a problem. That means the divisions can settle in and develop strong root systems before going dormant for the winter.
Come spring, instead of struggling to recover from being split, your perennials will be ready to burst into growth, looking better than ever. Dividing perennials in the fall is one of the easiest ways to refresh your flowerbeds, give your plants more life, and even create extra starts to share with friends or expand into new garden spaces.
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This Is My Garden is a garden website created by gardeners, for gardeners. Jim and Mary Competti have been writing gardening, DIY and recipe articles and books and speaking for over 15 years from their 46 acre Ohio farm. They publish three articles every week, 52 weeks a year. Sign up today to follow via email, or follow along!