Put on a pair of gloves when you work with monkshood plants. The plant's juices are dangerous if they come into contact with your skin. Cover any cuts or abrasions you may have before you handle monkshood. Prevent accidents by planting monkshood away from areas where children play. Keep this perennial away from vegetable gardens.
Place monkshood in organically enriched soil in a full- or partial-sun site. Plant your monkshood in full sunshine in areas where the summers are cool. In warmer climates, give the plant some afternoon shade. Monkshood grows in U.S. Department of Agriculture plant hardiness zones 3 through 7, but it does not thrive in those warmer zones in the hottest weather.
Keep the soil damp for the best results. Situate the plants in ground with good drainage. If the ground dries out and remains dry, monkshood will be stunted.
Prune back the stems on monkshood after it flowers to promote the possibility of late-season blooming. Monkshood may grow as high as 36 inches, so you may have to support the stems by staking them, especially when they plants produce flowers.
Divide and replant monkshood in the springtime or autumn, if you find yourself with too many plants. Monkshood is a slow-growing species, so you probably will not have to do this often.