Growing and Dividing Rhubarb in September

Rhubarb is a perennial favorite—bold, tasty, and virtually indestructible. September is the ideal time to give your patch some attention: dividing old plants invigorates tired clumps, multiplies your crop, and gives you an easy way to share with friends (or start a new bed!). Whether you’re expanding your garden, reviving an old root, or simply giving your crowns a boost, this guide walks you through the process.

Why Divide Rhubarb in September?

• Boosts productivity: Over time, rhubarb crowns get congested and lose vigor. Dividing brings new life and larger, juicier stalks next spring.
• Avoids rot and crowding: Tight, overcrowded crowns are more prone to disease and rot.
• Best establishment: Warm soil, increasing moisture, and moderate weather in September make it ideal for strong root development before winter.

When to Divide Rhubarb

• Wait until foliage begins to yellow and die back, signaling natural dormancy. This is usually mid- to late September.
• Avoid dividing during a heatwave or cold spell—mild, moist weather is best.

Step-by-Step: Dividing and Planting Rhubarb

1. Lift the Crown

• Use a garden fork to dig around the clump, loosening soil about 20–30cm (8–12”) from the base.
• Lift the whole crown gently, keeping as many roots intact as possible.

2. Divide the Clump

• With a sharp spade or knife, slice the crown into sections. Each division should have at least one strong bud (“eye”) and a good root portion.
• Remove and discard any rotting, blackened, or weak pieces.

3. Prepare New Planting Sites

• Rhubarb loves well-drained, fertile soil and a spot in sun or light shade.
• Dig a hole twice the width of each division and mix in well-rotted compost or manure (don’t let manure touch the bud directly).

4. Plant & Water In

• Set the crown so the top bud is 2–3 cm below soil level. Space plants at least 75–90cm (30–36”) apart.
• Backfill and firm in well.
• Water thoroughly and mulching with straw, compost, or leaves helps keep moisture in.

Ongoing Care

• No stalk-pulling until next year: Let new divisions build strength through autumn and spring before harvesting.
• Remove flower spikes ASAP: Divert energy into roots, not seed production.
• Keep well-watered in dry spells until plants are established.
• Mulch annually in autumn or early spring with compost or manure to nourish crowns.

Reviving Old, Neglected Crowns

If you inherited a rhubarb bed or haven’t divided in years:

• Remove and destroy any totally dead or diseased parts.
• Only keep healthy, solid, “budded” pieces for replanting.
• Enrich soil with organic matter—and in heavy clay, double-dig and add grit.

Harvest Tips

• Hold off first harvest until second spring after dividing.
• When picking, pull (don’t cut) stalks from the base for best plant health.

Extra Tips

• Crowns too small to divide? Just mulch and feed this year; divide next year if plants are bigger and stronger.
• Extra divisions make great gifts for friends and neighbors!

Conclusion

A little work in September pays dividends for years with juicier stalks, robust plants, and a thriving rhubarb patch that rivals any allotment champ. With good division technique and ongoing care, this undemanding perennial will keep your spring desserts and summer pies full for decades.