Use hay and cow manure to keep weeds from growing and continue to nourish the rhubarb plants. Leaf mulch or ramial wood chips also make good mulches. Your rhubarb bed should stay moist and well-drained throughout the heat of the summer. Water every time the soil begins to look dry. Seed stalks keep the rest of the rhubarb plant from growing tall and strong, since they use up the plant's energy. Rhubarb isn't prone to getting many pests, but you may notice a beetle called the rhubarb curculio on the stalks. This beetle is light gray and about half an inch long. Pick off the beetles one at a time. Don't use pesticide to kill them, as this may damage your rhubarb plants. After the first year has passed, use a light application of high-nitrogen fertilizer to encourage the rhubarb to come back healthy. Do this after the ground has started to thaw.
Place a layer of mulch over your rhubarb bed in the spring and fall. Keep the rhubarb watered during the summer. Remove seed stalks before they get too big. Pick off rhubarb curculio. Fertilize rhubarb every spring.