Castor for color, and because the critters don’t eat it! Castor is a large, colorful plant for warm season color in the Southwest. Indeed, it grows large enough for some shade too.
What is Castor
Castor (Ricinus communis) comes to us from eastern Africa and is now spread world-wide in tropical areas. Oil of the seeds was important in ancient Egypt, imported at great cost from the kingdom of Nubia. Any plant that could reap great profits was subject to “industrial sabotage” back in the day, which is how castor seeds ended up in India. Sorry for digressing dear readers, but these tales are what Ethnobotanists (that would be me) love to investigate. But you are here for the gardening goodies – so read on.
Planting & Care of Castor
Castor plants are striking ornamentals. Plants vary greatly in growth habit and appearance because plant breeders have been busy. They have selected for a wide range of leaf, flower, and seed pod 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 of your flower garden. I planted castor seed in among my citrus plants to help shade them, and help maintain a higher humidity level in the citrus “grove.”
Castor don’t stand freezing. I planted my seed outdoors in April, but Low Desert can plant in March. In cooler areas, start seed indoors and plant out once chance of frost is past.
As far as I can tell, any nice amended garden soil is fine. The ones planted in pure desert soil did not survive.
Castor plants prefer full sun, and can even tolerate reflected light, like near a pool. In fact, the higher relative humidity near a pool would make them happy. That said, do NOT plant them too close to your fish pond if you have one. Fallen leaves or other plant materials can kill fish. You can compost the leaves and stems though. Once they are well composted they pose no hazard.
This species is a tad needy of water, and should be kept evenly moist to get growing. Plants are from tropical areas with high humidity, thus in our area, they do best in a monsoon garden. If the rains are heavy, additional water may not be required.
Once seeds grow a set of true leaves, animals of all ilk do not bother castor plants. (They will try seedlings so you may have to protect them.) Ricin and other toxic compounds present in all parts of the plant also offer a degree of natural protection from insect pests, such as aphids. Byproducts of castor oil production have been investigated for use as an insecticide. The castor plant is a source for undecylenic acid, a natural fungicide.
Harvesting and Use of Castor
It is not recommended to attempt processing of castor oil at home. But do save some seed of your plants because the best thing to grow in your garden is what grew there!
Learn More about Southwest Gardening
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Read more about castor in my book “Father Kino’s Herbs: Growing and Using Them Today” (Tierra del Sol Press). I hope you will consider purchasing a copy locally at Antigone Books, Magic Garden, Mostly Books, Rillito Nursery, Tohono Chul, and Tucson Botanical Gardens. Call first to make sure they have copies left.
You can also buy Father Kino’s Herbs on Amazon (link). If you buy the book there the Horticulture Therapy non-profit Tierra del Sol Institute will get a few pennies – at no extra cost to you.
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