Castor Bean plants (Ricinus communis) are the source of two of the nastiest substances on earth. The first, is castor oil. YUCK! This nasty substance has been used to treat “digestive issues” for a long time. The taste of this stuff is so bad that it will make full grown men cry. I only had to take it once, but it is a memory that still haunts me. The other really bad thing that comes from this plant is ricin. Ricin is a by product of the process used to make castor oil. It is the most toxic substance on earth derived from a plant. This stuff is so toxic that a TINY amount of refined ricin was used to kill a Bulgarian defector in 1978. Georgi Markov was “shot” with a modified umbrella in the back of his leg with a tiny pellet the size of a pinhead. This tiny pellet had two holes drilled through it to form a tiny “X’ through the center. That space was filled with ricin. Within three days, that tiny, tiny amount of ricin had killed Georgi. Even though the ricin was not detected until after the autopsy, it would not have mattered. There is no antidote for ricin poisoning. Here is another scarey fact. Quantities of refined ricin were found in caves in Afghanistan right after the invasion.
If you decide to grow Castor Beans, you really need to be aware that every part of the plant is toxic. This includes the stems, leaves and the seeds. One bean (really a seed) is enough to kill a child. Two or more will kill most adults. If you have a dog that likes to chew plants, then don’t grow them where the dog can get to them. I would also not grow them if there are small children in the vicinity.
I grow and love this dangerous plant at my house. However, I have no pets or kids. I love them for several reasons. First, they are as lovely as they are dangerous. Most varieites will grow over 6′ in a single season. The large, eight lobed leaves provide a somewhat tropical effect. This look is often difficult to obtain in locations that have high light and low water. Castor Bean loves both of these conditions. They also come in a wide range of colors. Some varieties are a pale green, while others are very deep purple. In fact, one of the most stunning plant combinations I have ever seen was a large mass of the purple variety growing behind a huge stand of thornless prickly pear cactus at Dr. Bill Welch’s weekend place in Washington County.
The flower of the Castor Bean is lovely but not that impressive. The plant sends up spikes that develop small, pink flowers that attract a lot of pollenators. This year, they seem to be drawing more yellow jackets than bees. The base of the flower turns into a round, spikey ball. This ball contains the very deadly seeds. When the balls dry out, they fall to the ground. The spikes are designed to attach to the fur of wandering critters.
Castor Beans are also incredibly easy to grow in our climates. They love full sun, can take the heat and can survive low water once established. Originally native to the Mediterranean Basin, Africa and India, their use as an ornamental has now allowed them to spread to most tropical areas in the world.
Castor bean seeds are available from most seed companies. I get mine from Baker Creek Seeds (rareseeds.com). Plant the seeds about a half to one inch deep in full sun when the soil has warmed up to about 70 degrees. They are fairly heavy feeders and like a rich soil thoroughly worked with compost. They do take a while to germinate so be patient. Water regularly to get them established. Once the plant is about a foot tall, they will survive and thrive on 1 inch or less of water per week. They get tall quickly so you may need to stake them. Also, the large leaves are susceptible to wind damage.
Caster Beans have been grown in the south for a very long time. My grandparents grew them and their grandparents probably did as well. They are hardy, beautiful and a few plants can fill up a relatively large area in a garden with big, bold, vibrant foliage. If you take care to plant these where curious pets and children can’t get to them, you will enjoy a lush, tropical look in the yard in the driest of times.