Jacqueline Soule here today to talk about a great plant for the summer herb garden, castor bean (Ricinus communis). It is called ricio or higuerilla in Spanish, and called “blech” by small children dosed with it’s oil. It is a member of the Euphorbiaceae, the spurge or poinsettia family, which is widely considered a plant family to avoid consuming, so who first figured the oil was a good laxative and spring tonic?! Not only for internal use, but the oil was popular 3000 years ago for body lotion, hair dressing, and for lamp oil.
Yes, some highly effective medicines, insecticides, and uses of the oil come from the castor seeds (they are not botanically beans), but it is not a plant for home remedies. All parts of the plant contain both useful and highly toxic compounds. I mention the plant today because it was used in the Southwest starting in Father Kino’s time, indeed was planted in his mission gardens, plus it is a lovely ornamental plant. I like to grow castor in my modern day garden as a link to such ancestral gardens.
Castor beans are toxic due to ricin, a chemical present in the flesh of the seeds, but not present in the oil. Although the lethal dose in adults is considered to be four to eight seeds, reports of human poisoning are rare as the seed coat is quite durable and can pass intact through the human digestive system. Poisoning occurs when animals ingest broken seeds or break the seed by chewing.
Planting and Care.
Castor plants are striking ornamentals. They can vary greatly in growth habit and appearance. The variability has been increased by breeders who have selected a range of cultivars for leaf and flower colors, including scarlet, bronze, or maroon leaves, topped by large, decorative seed pods in shades of red, orange, or maroon. Plants make an excellent temporary screen or exotic backdrop for the back of the border.
Intolerant of frost, castor plants can be started indoors and planted out once the soils warm, or planted directly in the soil in spring. For best results, soak seeds in water for 24 hours before planting. The large seeds should be buried about one inch deep. Castor plants prefer full sun and should be kept evenly moist to get growing.
Harvesting and Use.
It is not recommended to attempt processing of castor oil at home. But do save some seed of your plants, as there is some effort to outlaw their sale.
If you live in Southeastern Arizona, please come to one of my lectures. Look for me at your local Pima County Library branch, Steam Pump Ranch, Tumacacori Mission (founded by Father Kino), Tucson Festival of Books and other venues. After each event I will be signing copies of my books, including the latest, “Southwest Fruit and Vegetable Gardening,” written for Arizona, Nevada and New Mexico (Cool Springs Press, $23).
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