Rhubarb

Rhubarb (Rheum rhabarbarum) is an undemanding perennial that will thrive in the same spot for decades — all it asks for is moist, fertile soil and a dose of compost now and then. Harvest the stalks from April to the end of June: pull them with a twisting motion at the base, never cut them. Stop harvesting from July so the clump can regenerate and oxalic acid doesn't build up in the stalks. Snap off flower stems as soon as they appear. The leaves are poisonous — they belong on the compost heap, not in the kitchen. Divide clumps in spring or in October.