Dividing Perennials: Step-by-Step

Why dividing perennials matters

Dividing perennials revives plants that have lost vigor, restores bloom production, and gives you free plants for other areas of your yard. Most perennials perform best when divided every 3-5 years.

Perennials naturally expand outward as they mature. The center of the clump — the oldest part — often becomes woody or completely dead while the outer ring continues growing. A hosta that produced 40 leaves in year three may produce 60 outer leaves and a hollow center by year eight. A clump of rudbeckia may have dozens of flowering stems at its edges and nothing in the center.

This is a natural process, not a sign of disease. The plant is allocating resources to the youngest, most vigorous growth at the outer edges. Division resets this cycle by removing the declining center and replanting vigorous outer sections.

The benefits of regular division:

• Restored bloom count: divided daylilies and hostas typically bloom more prolifically than undivided clumps
• Improved plant health: vigorous sections without the old woody center establish faster
• Free plants: one mature hosta clump can produce 4-8 divisions that cost nothing
• Controlled spread: aggressive perennials (bee balm, black-eyed Susan) are easily managed through regular division

When to divide: fall vs spring

Timing depends on when the plant blooms. Divide when the plant is not in active growth — either just after its bloom period ends (fall for spring bloomers) or just before it begins (spring for fall bloomers).

Fall division (August – October)

Best for:

• Spring bloomers (bleeding heart, iris, peonies — though peonies need care)
• Summer bloomers (hostas, daylilies, rudbeckia, coneflower, yarrow)
• Any perennial that flowered more than 6 weeks ago

Fall has the advantage of warm soil temperatures. Roots establish quickly in warm soil, giving the divided plant a head start before winter. The disadvantage: a late frost can heave newly divided plants out of the ground if they haven’t rooted deeply. Plant fall divisions at least 4-6 weeks before the first expected frost.

In Zones 5-7, fall division typically runs from late August through mid-October. In Zones 3-4, August through early September gives the best root establishment before cold arrives.

Spring division (March – April)

Best for:

• Fall bloomers (New England asters, goldenrod, Joe Pye weed)
• Ornamental grasses (always divide in spring when growth resumes)
• Any perennial with unknown bloom time (spring division is the safer default)

Spring division works because the plant’s energy is rising into new growth, helping the divided sections establish quickly. The disadvantage: spring rain can be unreliable, and early-emerging perennials (hostas, peonies) can be hard to see and locate before they push through the soil.

Timing summary by common perennials

Tools needed for dividing perennials

Keep tools sharp. A dull spade tears rather than cuts, causing more root damage. Wash and dry tools between plants if dividing multiple beds to avoid spreading disease.

How to divide perennials: step by step

Step 1: Water the day before

Water the clump thoroughly 24 hours before dividing. Moist soil clings to roots and makes them easier to extract cleanly. Dry soil falls away, exposing roots to air and slowing establishment.

Step 2: Cut back foliage (optional)

Cutting stems to 6-8 inches before digging reduces moisture stress on the roots after division. This is especially helpful in fall for plants with substantial leaf area (hostas, daylilies). Skip this step for plants you’re dividing in early spring when foliage hasn’t fully developed.

Step 3: Dig around the clump

Push a sharp spade in vertically around the entire clump, about 6-8 inches from the crown. Work around the full circumference before trying to lift. This cuts the outer roots cleanly and defines the root ball.

Step 4: Lift the clump

Lever the spade under the root ball and lift. For large, heavy clumps, insert a garden fork alongside the spade and use both handles as levers simultaneously. Set the clump on a flat surface (tarp, driveway) where you can work comfortably.

Step 5: Divide the clump

Divide large clumps into 3-5 sections for fast recovery. Smaller divisions are possible but take longer to establish and bloom.

Methods by plant type:

Fibrous-rooted perennials (hostas, daylilies, yarrow): Use two garden forks placed back-to-back in the center of the clump. Push the handles apart — the forks pry the clump into sections without cutting. For very dense clumps, use a sharp spade or pruning saw to cut through.

Rhizomatous perennials (iris, bee balm): Pull rhizomes apart by hand. Discard old, woody, or rotted sections. Plant only young, firm rhizomes with healthy roots attached.

Crown-forming perennials (rudbeckia, coneflower): Insert a spade through the center of the lifted clump to split it. Repeat to produce sections of the desired size.

Step 6: Inspect and discard

Before replanting, examine each division. Discard:

• Dead or hollow centers
• Rotted roots (soft, dark, mushy)
• Sections with fewer than 3-5 healthy shoots
• Any sections showing disease or insect damage

What you are left with should be healthy outer sections with green shoots and firm white or tan roots.

Step 7: Replant immediately

Replant divisions as soon as possible. Every minute out of the ground causes moisture loss. Set each division at the same soil depth it grew at before — most perennials planted too deep will not bloom the next season.

Firm the soil gently around each division to eliminate air pockets. Water thoroughly immediately after planting.

Aftercare for newly divided perennials

Newly divided plants need more attention than established ones for 2-3 weeks:

• Water daily for the first two weeks if rainfall is below 1 inch per week. Roots haven’t re-established and can’t draw moisture from as wide an area as before.
• Mulch with 2 inches of straw or shredded leaves to retain soil moisture and moderate temperature.
• Do not fertilize immediately. Wait 2-4 weeks before fertilizing. New divisions need to root before they can use nutrients — applying fertilizer too soon can burn vulnerable root tissue.
• Watch for wilting. Some leaf droop is normal for 2-3 days after division. If wilting continues past 5 days, shade the plant with a floating row cover for 1-2 weeks.

For fall divisions, apply a 3-4 inch mulch layer after the first hard frost to protect against frost heave through winter. Remove the mulch in early spring before growth resumes.

Perennials that should NOT be divided

Some perennials resent disturbance and perform worse after division. Do not divide:

• Baptisia (false indigo) — extremely long-lived; has a deep taproot; division usually kills it
• Gas plant (Dictamnus) — takes 5-7 years to reach mature size; division sets it back dramatically
• Hellebore — resents division; spreads by seed instead; transplant self-sown seedlings
• Bleeding heart (Dicentra) — can be divided but slowly; prefers to be left alone
• Japanese anemone — spreads by runners; control by removing runners, not dividing the crown
• Globeflower (Trollius) — rarely needs division; leave undisturbed in moist soil

Building your perennial garden through division

Division is one of the fastest ways to fill a new garden bed cheaply. A single mature hosta clump can yield 6-8 transplantable divisions. A large daylily bed can provide dozens of divisions in a single afternoon.

For a strategy on building fall interest through perennials — including the best fall-blooming species that benefit from regular division — see our fall perennials guide.

For more on hostas — which are among the most commonly divided perennials in US gardens — see our hostas care guide. And for coneflowers (Rudbeckia and Echinacea), which need division every 2-3 years to maintain performance, our coneflower guide covers the specific division timing and replanting steps for these native plants.

Quick reference: dividing common perennials

Penn State Extension offers a detailed perennial division guide with photographs of the fork-method technique and species-specific timing for northeastern US climates: extension.psu.edu.