Rhubarb
Rheum rhabarbarum
The stalks are food and the leaves are genuinely poisonous. Do not confuse the two.

The leaves are toxic
Rhubarb leaf blades contain oxalic acid and other compounds at levels that cause real harm - kidney damage in serious cases. Only the stalk is edible. Cut the leaf off in the garden and compost it (composting is fine; the oxalic acid breaks down and does not transfer to soil in meaningful amounts).
Plant crowns, not seed
Buy dormant crowns and plant in early spring or autumn with the buds an inch or two below the surface. Seed-grown rhubarb is variable and slow. Space three to four feet apart - a mature plant is large.
Wait before harvesting
Take nothing in the planting year. In year two, take a few stalks over a couple of weeks. From year three, harvest fully for eight to ten weeks in spring. Same logic as asparagus: early harvesting permanently weakens the crown.
Pull, do not cut
Grip the stalk low, twist and pull sideways so it comes away cleanly at the base. A cut stump can rot back into the crown. Never take more than about two-thirds of the stalks at once.
Stop by midsummer
Stop harvesting around late June or early July and let the plant rebuild for the rest of the season. Continuing all summer exhausts the crown and reduces next year sharply.
Remove flower stalks
Rhubarb sends up a thick flowering stalk, especially in older or stressed plants. Cut it out at the base as soon as you see it - flowering diverts a lot of energy from the crown and signals that division may be due.
Feeding and division
A heavy feeder. Top-dress with compost or well-rotted manure every autumn. Every five to eight years, lift the crown in early spring and split it into pieces with at least one strong bud each, discarding the woody centre. This restores vigour and gives you plants to share.
Storage and use
Stalks keep a week or two in the fridge and freeze extremely well chopped, raw, with no blanching. Early spring stalks are the most tender; later ones get stringy and can be peeled. Rhubarb needs sugar and pairs classically with strawberry, which conveniently ripens at the same time.
- First harvest
- Year 2-3
- Spacing
- 3-4 ft
- Sun
- Full to part
- pH
- 6.0-6.8
- Hardy
- Needs winter chill
- Harvest
- Spring to midsummer
- Productive life
- 10-15 yrs
- Divide
- Every 5-8 yrs