Divide Perennials Now: Free Plants Forever

Perennial division is gardening’s closest thing to free money. Take one $15 hosta, divide it into five plants, and you’ve created $75 worth of landscape value in 20 minutes. Multiply that across your entire perennial collection and you’re looking at hundreds of dollars in saved nursery costs while improving plant health and vigor.

October is prime division season for most perennials. Cool temperatures reduce transplant stress, fall rains provide natural irrigation, and plants have months to establish before summer stress arrives.

Why Divide Perennials

Rejuvenate declining clumps: Perennials decline as they age. Centers die out, bloom production drops, plants look shabby. Division resets the clock, creating vigorous young plants from tired old clumps.

Control aggressive spreaders: Some perennials (bee balm, obedient plant, asters) spread relentlessly. Division keeps them in bounds while providing material to fill other areas.

Multiply your investment: One $20 perennial becomes five plants. Fill new beds, trade with friends, donate to community gardens.

Improve flowering: Many perennials bloom best on young growth. Division forces new growth, dramatically improving flower production.

Which Perennials to Divide in Fall

Excellent candidates for fall division:

• Hostas
• Daylilies
• Peonies (best divided September-October)
• Siberian iris
• Bee balm (Monarda)
• Asters
• Sedum
• Black-eyed Susan (Rudbeckia)
• Coneflowers (Echinacea)
• Ornamental grasses (best in fall)
• Coral bells (Heuchera)
• Catmint (Nepeta)

Wait until spring to divide:

• Salvia
• Lavender (doesn’t divide well, use cuttings instead)
• Yarrow
• Lamb’s ear
• Russian sage
• Butterfly weed (Asclepias) - resents division

Never divide in fall (spring only):

• Astilbe (fall division often fails)
• Garden phlox (Phlox paniculata)
• Primrose

Division Timing by Plant Type

Early fall (September):

• Peonies (absolutely must divide in fall)
• Poppies
• Bearded iris (August-September)

Mid-fall (October):

• Hostas
• Daylilies
• Ornamental grasses
• Asters
• Most perennials

Late fall (November in mild climates):

• Can extend division of hardy perennials if ground isn’t frozen
• Risk increases with later timing

General rule: Divide 4-6 weeks before ground freezes to allow root establishment.

Tools and Materials

Essential tools:

• Sharp spade or garden fork
• Sturdy knife or hori-hori
• Pruning saw (for tough woody crowns)
• Tarps (to work on, contain mess)
• Buckets (to hold divisions temporarily)
• Labels and markers
• Watering can or hose

Optional but helpful:

• Two garden forks (for leverage on massive clumps)
• Root pruners or loppers (for thick roots)
• Wheelbarrow (to move heavy clumps)
• Compost or soil amendments

Division Technique by Plant Type

Hostas

When to divide: October is ideal. Every 4-5 years for most varieties.

Technique:

1. Cut back foliage to 6 inches (easier to handle)
2. Dig around entire clump, 6 inches beyond drip line
3. Pry entire clump out with fork
4. Wash roots with hose to see natural division points
5. Identify “eyes” (growing points for next year)
6. Use sharp knife to cut between eyes
7. Each division needs 2-3 eyes minimum
8. Replant immediately at same depth

Tip: Young hostas (under 3 years) shouldn’t be divided. Wait until they’re substantial clumps.

Daylilies

When to divide: October, or anytime when not actively blooming. Every 3-4 years.

Technique:

1. Cut foliage back to 8-12 inches
2. Dig entire clump (roots are extensive)
3. Shake off excess soil
4. Look for natural division points
5. Pull sections apart by hand (usually works)
6. For stubborn clumps, use two forks back-to-back and pry apart
7. Hose off roots, trim any damaged portions
8. Replant with crown just at soil surface

Tip: Daylilies tolerate brutal division. You can literally chop clumps with a sharp spade into quarters.

Ornamental Grasses

When to divide: Fall only (spring division often fails). Every 3-5 years before they die out in center.

Technique:

1. Cut foliage to 6-8 inches
2. Dig entire clump
3. For small grasses, pull apart by hand
4. For large clumps, use saw or axe to cut into sections
5. Each division should be 6-8 inches across minimum
6. Discard dead center sections, keep vigorous outer growth
7. Replant at original depth

Tip: Large grasses (miscanthus, pampas) require serious tools. Chainsaw or reciprocating saw works for massive clumps.

Peonies

When to divide: September-October ONLY. Spring division usually fails.

Technique:

1. Cut stems to ground
2. Mark plant position before digging
3. Dig 12 inches beyond stems in all directions
4. Lift entire root crown carefully
5. Hose off soil to expose “eyes” (red/pink buds)
6. Cut divisions with 3-5 eyes each
7. Let divisions air-dry for 24 hours (prevents rot)
8. Replant with eyes 1-2 inches below soil surface (CRITICAL - too deep and they won’t bloom)

Tip: Peonies resent division and may not bloom for 2-3 years after. Only divide if absolutely necessary.

Bee Balm and Aggressive Spreaders

When to divide: Fall. Every 2-3 years to control spread.

Technique:

1. Dig sections you want to keep
2. Remove and discard sections that spread too far
3. Replant keepers in amended soil
4. Consider root barriers to contain future spread

Iris

Bearded Iris:

• Divide August-September (6 weeks after bloom)
• Dig clumps, separate rhizomes
• Trim foliage to 6 inches
• Discard old, woody centers
• Keep young rhizomes with healthy fans
• Plant with rhizome top exposed to sun

Siberian Iris:

• Divide in fall (October)
• Dig entire clump
• Cut into sections with sharp knife or spade
• Each piece needs several fans
• Replant immediately

Replanting Divisions

Site preparation:

1. Amend soil with 2-3 inches compost
2. Dig holes wider than root spread
3. Create slight mound in hole center
4. Plant at original depth (or specific requirements like peonies)

Planting:

1. Spread roots over mound
2. Backfill with amended soil
3. Firm soil gently
4. Water thoroughly
5. Mulch 2-3 inches (keep away from crown)

Spacing:

• Small divisions: 12-18 inches apart
• Medium perennials: 18-24 inches apart
• Large perennials: 24-36 inches apart
• Remember they’ll fill in over 2-3 years

Post-Division Care

Watering:

• Water deeply immediately after planting
• Keep soil evenly moist (not soggy) through fall
• Reduce watering after ground freezes
• Resume regular watering in spring

Mulching:

• Apply 2-3 inches mulch after planting
• In cold zones, add extra mulch after first hard freeze
• Pull back mulch slightly in spring as growth begins

Fertilizing:

• Skip fertilizer at planting
• Light compost top-dressing is beneficial
• Begin regular feeding second growing season

First-Year Expectations:

• Divisions may not bloom first year (energy goes to root establishment)
• Some foliage growth expected before dormancy
• Full-size plants typically by third year

Sharing and Trading

Perennial swaps:

• Organize with gardening friends
• Community gardens often hold plant swaps
• Local garden clubs facilitate trading
• Post on neighborhood apps

Gifting divisions:

• Pot up divisions for gifts
• Include care tags with plant name and requirements
• Share with new gardeners (hostas and daylilies are foolproof)

Selling:

• Plant sales at schools, churches
• Farmers markets (check regulations)
• Online marketplaces
• Specialty perennials can command good prices

Common Division Mistakes

Dividing too small: Tiny divisions take years to reach substantial size. Err toward larger divisions unless multiplication is your goal.

Planting too deep: Many perennials rot if crown is buried. Plant at original depth.

Waiting too long between divisions: Massively overgrown clumps are brutal to divide. Stay ahead of the growth.

Dividing at wrong season: Spring vs fall matters for some species. Follow guidelines.

Neglecting water after planting: Fall divisions still need establishment water, especially if fall is dry.

Long-Term Division Schedule

Create a rotation schedule so you’re dividing a few plants each year rather than facing overwhelming work all at once.

Year 1: Divide hostas and daylilies Year 2: Divide asters and bee balm Year 3: Divide ornamental grasses Year 4: Divide iris and other perennials Year 5: Return to Year 1

This spreads work across years and ensures all perennials get divided on appropriate cycles.

Want to plan your perennial divisions and visualize how the new plants will fill in? Gardenly’s AI design tool  generates planting plans showing optimal division timing, spacing, and how your garden will look as divisions mature.

October’s perfect division weather won’t last. Grab your spade this weekend and start multiplying your perennial investment into a garden full of free plants.