how to grow castor bean plant Rican s communist the caster being plant reeking as communes walks a fine line between landscape acceptable ornamental and highly toxic weed it grows fast reaching six to ten feet tall in a few months in US Department of Agriculture plant hardiness zones 9 through 11 it grows as a perennial but with the fast growth rate that works well as an annual in frost prone areas this plant is only suitable for areas where children and pets never go because the whole plant is poisonous and it's bright red seeds especially so spacing and landscape suitability the castor bean plant needs full Sun and lonely soil with fast drainage to create a dense planting without causing crowding leave at least four feet between plants because of the highly toxic nature of the seeds leaves and stalks never grow this ornamental in areas where children and pets have access to the garden the seeds are the most poisonous part of the plant they fall naturally in the fall creating a potentially toxic hazard at ground level watering and drought tolerance to support the rapid growth castor bean plants need abundant water early in the spring and summer water once a week giving each plant a total of one inch of water at each watering session apply it slowly with a hose or soaker hose so water can seep down around the roots adding a lot of water all at once will cause it to run off and away from the roots after castor bean plants reach their mature height a brief period of drought won't damage your slow growth fertilizer for sustain growth regular fertilizer through the growing season keeps a castor bean plant growing strong and lush once a month apply a general purpose fertilizer such as a 10 20 10 5 10 5 or a 10 10 10 formula use half cups for a 100 square foot area around the plants once you finish fertilizing water the soil with one inch of water this should replace one of the regular weekly waterings when damage and staking ideally grow ornamental castor bean plants in a protected area as strong winds can break the stalks and shredded leaves making the foliage look ragged in windy spots keep the plants from falling over with Stakes drive a stake 10 to 12 feet tall or as tall as the height of the plant into the soil 12 inches from the base and loosely tie the stem to the stake preventing spread and toxic poisoning keep castor bean plants from taking over the garden by clipping the flower heads before they produce seeds but you have to get every single one this also helps keep the toxic seeds off the ground clip flower stalks where they attach to the stem and wash the shears with soap and water in cold areas they will die with the first frost remove dead plants and discard them in the garbage all parts are poisonous so don't put them in the compost you