Give rhubarb some space

Lift and divide congested rhubarb clumps, as they'll start producing spindly stems and bolting if you let them get overcrowded. Tip plenty of well-rotted manure into the planting hole: dig up the whole clump and split it with a spade into lumps of root, each with a bud attached. Replant in rich, moist soil in a sunny spot.