The castor bean is a rapidly-growing perennial plant known for its lush foliage and large flower stalks. The plant's floppy branches sometimes need help to prevent them from sprawling on the ground or breaking during a windy season. Build a simple bamboo trellis and secure the plant against the trellis to lend support to the castor bean so you can enjoy it for many years to come.
Drive a 4- to 5-foot tall bamboo pole 8 to 12 inches into the ground in the area where the castor bean plants will grow. Dig the pole deep enough so that it is sturdy and does not lean.
Insert four more bamboo poles into the ground vertically to form a square around the center pole, ensuring that each corner is 2 feet from the center pole.
Bend the four outside poles toward the middle pole. Secure them to the middle pole using garden twine, string or similar tying material to form a basic teepee-like structure.
Plant the castor bean seeds in a circle around the center pole, 6 inches from the center pole and 4 to 6 inches from each other. Sink each seed 1 inch below the surface of the soil.
Water the castor bean seeds twice daily or as needed to keep the soil moist. The seeds will germinate within 10 to 14 days. Continue to water daily until the castor seedlings are 4 inches in height.
Pile 2 inches of mulch around the castor bean seedlings when they've reached 4 inches in height. Reduce watering to once every 4 to 6 days, applying enough water each time to moisten the soil to a depth of 5 inches.
Tie the branches of each seedling loosely to the teepee structure as soon as the branches of the plant are long enough. Wrap the branches around the bamboo poles in an upward direction as they grow. Once trained onto the structure, the castor bean plants will climb it on their own.