A perennial is a plant that lives through multiple growing seasons. These plants typically die down in the winter, leaving healthy root systems belowground. When warmer weather arrives, the plants sprout healthy new growths.
If you have a perennial garden, you’re already headed for year-round beauty. But did you know you can divide the plants to improve their growth and expand your collection?
This article will show you how and when to split perennial plants for the best results. Then, we’ll show you 20 perennial plants you can divide for a flourishing garden.
Why You Might Need To Divide Plants
Division is the process of splitting an established plant into multiple pieces to create new plants.
Perennial division typically fulfills one of the following needs:
- Slow the spread of rapidly growing plants
- Improve the growth and vigor of existing plants
- Increase the number of plants in a collection
No matter your reason for splitting your plants, you must consider each species’ root type before breaking out the garden spade. The following section will discuss how to divide different plants.
How To Divide Perennial Plants
The first step in dividing a perennial is to excavate the parent plant from the ground.
Dig around each side of the plant with a garden fork. Pry the entire root ball from the bottom, shaking away clumps of soil and debris. Now you’re ready to start dividing.
Your method of division will depend on the plant’s root system.
| Root Type | Characteristics and Division Process |
| Spreading | Thin, numerous roots that mat together, sometimes overcrowding their centers. Most common perennial root system. Divide spreading root systems by pulling, prying, or cutting them apart. |
| Clumping | One central root clump with fleshy growths. Divide them by cutting the main section with a sharp knife. |
| Rhizomes | Horizontal underground stems that produce roots and plant growths. Remove old rhizome sections to improve the plant’s health. Create new divisions by removing a portion of the rhizome but leaving a few inches for the parent plant. |
| Tuberous | Thick root sections called tubers store nutrients underground. Cut tuberous roots into quarters, ensuring each division has a growth bud and piece of the original stem. |
When To Divide Perennials
A plant’s specific timing and frequency needs for division depend primarily on its species. However, you can follow general guidelines to promote healthy division and growth for any perennial.
For example, you can tell a perennial might need division if it’s producing small, weak blooms or sparse foliage.
The Clemson Cooperative Extension provides tips for adequately timing perennial division:
- Divide your perennials on a cloudy day with light rain. Avoid division on a hot day when the sun could damage vulnerable, exposed roots.
- Divide perennial plants every three to five years, depending on the species. Divide rapidly spreading plants more frequently to prevent crowding.
- A common rule of thumb is to divide perennials when they aren’t in bloom. Divide spring bloomers in the fall and fall bloomers in the spring. This allows the plant to dedicate its energy to developing roots instead of sprouting flowers.
- Replant fall divisions at least six weeks before the ground freezes and spring divisions several weeks before hot weather arrives.
20 Perennials You Can Divide
Now that you know some tips and tricks for plant division, we’ll show you 20 perennials you can divide for a fuller, healthier garden.
Daylilies
Daylilies are lovely summer perennials that produce grassy foliage and bold flowers.
Daylilies aren’t true lilies but are part of the Hemerocallis flower family. These plants are hardy, adaptable, and low-maintenance, blooming year after year with little care.
Daylilies are also low-maintenance when it comes to division. Divide them every three to six years or when you’d like to increase your collection. Start the process in the late summer after the final bloom.
Hostas
Hostas are low-maintenance foliage plants with bold, ornamental leaves. Their broad, supple greenery comes in green, teal, yellow, and variegated varieties.
When you’d like to increase your hosta collection, simply take a root wedge from an established plant in the early spring or fall.
Hostas have clumping root systems you can divide by cutting down through the middle of the plant with a sharp knife.
However, you should avoid dividing these plants too often; frequent division could inhibit optimal growth.
Peonies
Peonies – scientifically called Paeonia – are lovely summer bloomers known for their pink blossoms. These beauties are quite hardy and need little care to thrive.
You only need to divide these perennials if you’d like more plants – routine division for improved growth isn’t necessary.
Peonies have fibrous and tuberous roots. Expand your collection by cutting divisions from the center of the plant, ensuring each new section has several developed buds.
Place your peony divisions about an inch into the soil to start new plants.
Asters
Asters are late summer bloomers that produce daisy-like flowers in yellow, purple, and white hues.
They’re known to spread aggressively, so division is necessary to prevent crowding.
Divide your asters every one to two years in the spring. Depending on the species, you may need to use a division method suited for spreading roots or rhizomes.
After dividing the plant, replant the fresh outer growths and throw away the old center from the parent.
Bearded Iris
Bearded irises are hardy ornamentals that enhance a garden with bold, impressive blooms.
These perennials come in various colors and have drooping lower petals called falls, which are perfect landing pads for essential pollinators.
Bearded irises grow from rhizomes that need division every three to four years. Divide your irises on this schedule to encourage healthy growth and prevent the plants from overspreading.
The Wisconsin Horticulture Division of Extension recommends dividing irises after they bloom so replanted sections have time to develop before freezing temperatures arrive.
Sedums
Sedums are succulent plants that grow in various shapes and sizes. Their fleshy stems and leaves store water, making them drought-resistant and heat-tolerant.
“Autumn Joy” sedums are a popular variety known for their thick leaves and large flower heads that bloom throughout the fall.
Although sedums rarely need dividing to survive, it can help revive them after several years of growth. If you notice the center of the plant dying, take clump divisions to improve its vigor. Divide the plant in the early spring to prepare new growths for the blooming season.
Astilbe
Astilbes are lovely spring bloomers that add dimension to your garden with tall, plume-like flowers. They’re excellent at bringing a burst of color to shaded garden areas.
These perennials have fast-growing root systems that can overcrowd the parent plant over time.
Divide the plants every two to three years to promote healthy new blooms. Division should take place in the early spring or fall to allow the plant to establish itself before the growing season arrives.
Geraniums
Geraniums are stunning ornamentals that produce flowers in lavender, white, red, pink, and purple shades.
These flowers are intolerant of heat and drought, so apply mulch and fertilizer if you notice droopy sprouts.
If that doesn’t improve their health, you may need to divide them every two to four years to prevent overcrowding and soft blooms.
Divide them in the spring or fall by digging up the entire root ball and separating it into new sections.
Bee Balm
Bee balm – also known as Monarda – is an edible perennial and ornamental flower.
Bee balm’s bushy green foliage is accompanied by spiky pink, red, purple, and white summer blooms. The flowers have a heady fragrance popular amongst pollinators and tea lovers alike.
Bee balm plants have spreading root systems that grow rapidly. Improve your bee balm’s hardiness by dividing it every three years. Routine divisions will quell the plant’s rapid growth while reducing the risk of powdery mildew disease. Explore our article for a guide on growing bee balm and additional information about this plant.
Bleeding Hearts
Bleeding hearts are unique spring-blooming perennials you can plant in your garden. Their lovely segmented leaves sprout dangling heart-shaped flowers in various pink shades.
Bleeding heart plants need division less frequently than other perennials. Ideally, you’ll divide the plants every five years to promote growth and grow your collection.
When you split them, do so in the early spring – taking caution around their fragile root systems.
Coreopsis
Coreopsis flowers are a beautiful addition to summer gardens for their bright yellow blooms. It is one of the flowers that appeal to pollinators. They’re low-maintenance perennials that typically tolerate heat, drought, humidity, and pests.
These plants tend to die back after a few seasons because of their rapid flowering during the growing season. Care for your coreopsis by refreshing the plant every few years.
Divide your coreopsis every two or three years in the late spring, discarding weak roots as you go. This will allow the original plant and new divisions to supply their energy to smaller sections.
Lamb’s Ears
Lamb’s ear (Stachys byzantina) is an herbaceous perennial known for its thick, velvety soft leaves. The NC State Extension recommends planting lamb’s ears in a sensory or children’s garden to provide visitors with some fuzzy, comforting foliage.
Lamb’s ears have a spreading habit that translates underground to their systems of densely matted roots.
Reduce crowding by dividing the plant every few years in the spring or early fall. While splitting the plant, improve future growth by throwing away weak centers.
Coneflowers
Coneflowers are hardy perennials that bloom in lovely purple shades. The plant gets its scientific name, Echinacea, from the Greek word for hedgehog because of its spiky brown center.
Coneflowers don’t require frequent division, but splitting the plant every three or four years can improve its health. Prevent the plant from overcrowding by dividing it in the spring or fall.
Coneflowers have spreading root systems, so you should be able to separate them by prying or cutting them apart.
Black-Eyed Susans
Black-eyed Susan (Rudbeckia hirta) is a popular perennial known for its gold petals and dark, round center. These lovely wildflowers grow from a mound of dark green foliage that sprouts numerous blossoms.
Black-eyed Susans rarely need division for proper growth, but it can help prevent them from overcrowding.
Divide these plants every three or four years in the early spring. A properly timed division will allow these stunners time to develop before the summer blooming season.
Read our detailed article to see everything about black-eyed Susan.
Chrysanthemums
Chrysanthemums are one of the most popular fall flowers in the United States. These ornamentals, lovingly known as “mums,” will grace your garden with vibrant color up until winter.
Garden mums, in particular, are hardy perennials that grow back year after year with proper care.
After growing for multiple seasons, mums may start to overcrowd and grow fewer, weaker flowers. Help your chrysanthemums thrive by dividing them every couple of years. Read our article to learn everything about growing chrysanthemums.
Yarrow
Yarrow is a common perennial known for its flower heads of tiny, delicate blossoms. The plant is named Achillea millefolium after the Greek legend Achilles, who was said to use the plant’s medicinal qualities to heal wounded warriors.
Yarrow tends to be weedy, so you should select a sterile variety to prevent overcrowding. Encourage healthy growth by dividing the plant every two years in the spring or fall, or as you notice its center drying out.
Blanket Flowers
Blanket flowers are a species of the Gaillardia genus of sunflower-like perennials. Blanket flowers are prized in home gardens for their delightfully sunny blossoms that range in color from fiery orange to blood red.
These plants are sometimes called short-lived perennials, meaning they only persist through a few seasons.
Keep your blanket flowers strong and vigorous by dividing them every year or two. Divide and replant them in the spring in time for their early summer bloom time.
Read also: Spring bulbs for beautiful summer blooms
Garden Phlox
Garden phlox (Phlox paniculata) is a flowering perennial known for its vibrant blossoms. These flower heads of stunning blue, purple, and pink shades grow in loose clusters atop bright green foliage.
Keep your garden phlox healthy by dividing its roots every three to four years in the spring or fall. Tall phlox varieties need more frequent divisions to prevent them from overcrowding.
Create divisions by pulling or cutting the phlox’s roots into new sections.
Bellflower
Bellflowers (Campanula rotundifolia) are herbaceous perennials that often produce lovely, cuplike flowers. Many other colors, shapes, and height varieties are among the plant’s cultivars.
One popular variety is the bluebell, known for its light blue hue and delicate bell-like flower shape.
Divide your bellflower’s roots in the spring or fall by pulling apart sections from the parent plant. Do this every few years as the plant shows signs of drying or overcrowding.
Ornamental Grasses
Ornamental grasses are perennial plants that typically survive two or more years in the right conditions. Many of these grass varieties have spreading habits that make them excellent for landscape design.
You should divide ornamental grasses every three or four years to keep them growing healthy and strong. Make divisions in the spring, giving the plants time to develop root systems before summer. Avoid fall divisions that leave young cuttings susceptible to freezing temperatures. You can also read our informative guide to learn more about frost prevention tips for your garden.
Ornamental grasses typically have dense, fibrous root systems that should be divided with a sharp knife or saw.
Final Thoughts
Now that you know the best plants to divide, you can start building a collection of perennials without ever leaving your backyard.
Remember that timing and root type matter, so research your specific plant’s needs before breaking out the garden shears. Luckily, most perennial plants have similar root systems, so you can learn the process once and repeat it every few years as needed.
You’ll be well on your way to growing an ever-expanding garden of healthy perennial plants.
