Dividing Rhubarb: When to Split Crowns and How
Dividing rhubarb renews an old clump plus gives you new plants. University of Maine Extension says crowns should be split at least every four to five years. Split sooner when the plant makes many small stalks instead of fewer large ones.
The short answer
Dividing rhubarb means cutting the crown into pieces that each hold buds plus roots. Iowa State says to dig plants in early spring before growth begins. Each piece needs at least 2 or 3 buds plus a portion of root. Replant right away. SDSU says to space divisions 3 feet apart.
When should you divide rhubarb?
UMaine says spring splitting is preferred over fall. The plant then gets the full season to rebuild roots before winter. Divide the crown before the leaves develop. If you must divide in fall, UMaine says do it mid to late September. Leaves will not regrow by then, yet it comes before freezing temperatures. NDSU says to divide plus reset plants about every fourth year.
| Option | What it does | Source |
|---|---|---|
| Early spring | Preferred time | Growing rhubarb in Maine (Bulletin 2514) |
| Mid to late Sept | Fall option | Growing rhubarb in Maine (Bulletin 2514) |
| Every fourth year | Reset beds | Rhubarb and asparagus |
How do you split the crown?
Iowa State says dig deeply to get a large portion of the roots. Split large clumps with a sharp spade or butcher knife. UMaine says rhubarb buds grow with natural separations, so use those weak points. Each piece should have one to two buds plus at least a 2 inch cross section of storage root per eye. SDSU wants two or three buds per piece, roots attached.
Sharp spade: cut the clump. Natural gaps: split here. 2 or 3 buds: per piece.
How do you replant divisions?
Iowa State says set each section upright with buds 1 to 2 inches below the soil. Space plants about 3 feet apart plus water well. Roots must not dry out before planting. SDSU says replant at the same depth the crown grew before. NDSU suggests rows 5 feet apart with plants 3 to 4 feet apart in the row.
1 to 2 inches: bud depth. 3 feet: plant spacing. 5 feet: row spacing.
Troubleshooting
Many thin stalks? UMaine says that is a sign to split the crown.
Roots dried out? Iowa State says to bag clumps plus store them cool plus dark until planting.
Weak regrowth after fall division? UMaine says splitting too early in fall can let leaves regrow.
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Sources
- Growing rhubarb in Maine (Bulletin 2514), University of Maine Cooperative Extension
- When can I transplant rhubarb?, Iowa State University Extension, Yard and Garden
- Rhubarb: how to grow it, South Dakota State University Extension
- Rhubarb and asparagus, NDSU Extension
FAQ
How often should rhubarb be divided?
UMaine says at least every four to five years. NDSU says about every fourth year.
Can you divide rhubarb in fall?
Yes. UMaine says mid to late September, before freezing, though spring is preferred.
Can rhubarb be grown from seed?
NDSU says plants from seed seldom equal named varieties, so division is preferred.
How far apart should rhubarb be planted?
Iowa State plus SDSU say about 3 feet apart.
How many buds should each division have?
Iowa State says at least 2 or 3 buds with a portion of the root system.
