C is for Castor! Castor for Color. Castor because the Critters don’t eat it! Colorful Castor is a large, showy plant for warm season color anywhere in the Southwest.   Thus “Si!” is for castor as well!

What is Castor?     

Castor (Ricinus communis) comes to us from eastern Africa and is now spread world-wide in tropical areas. Oil from the seeds was once very important in ancient Egypt. It was used for medicines for royalty, and even for cosmetics. It was once imported at great cost from Nubia.

Since castor oil commanded solid gold, it was the target of what would today be considered “industrial spying and sabotage.” Seeds were smuggled out of Nubia and sold for vast sums. Meanwhile, some castor fields were salted to prevent rival farmers from growing this pricey crop.

The seeds of castor were smuggled to India by Arab traders, and plantations worked by slaves made money for those traders. I am getting a tad far afield (pardon the pun) here, but plants are an integral part of the history of the world – a part often forgotten except by Ethnobotanists, like myself. (Ethnos = peoples, thus Ethnobotanists look at how people use plants.)

But this is a gardening website, and you are here for the gardening goodies – so read on.

Why Plant Castor?

Castor plants are striking ornamentals.    They are generally annuals, but they may survive for a few short years.

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.”

Planting & Care of Castor

Castor is planted from seeds.  Seeds are mostly shared between plant lovers, because of the liability associated with selling them.  Come to our next seed swap – generally mentioned in my free Substack newsletter that you already signed up for – didn’t you?  There’s a link on each page of this site.

Soil (Earth)

As far as I can tell, any nice garden soil is fine.    The ones planted in pure desert soil did not thrive. So I’m going to say soil pH should be below 7.5.  Well drained soil too – not clay.

Temperature (Air)

I planted my seed outdoors in April, but Low Desert can plant in March.    Castor are not very tolerant of frost, so in cooler areas, start seed indoors and plant out once chance of frost is past.   

Light (Fire)

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.   

Water

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.

Castor & “Pests”

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.    By-products of castor oil production have been investigated for use as an insecticide.    The castor plant is a source for undecylenic acid, a natural fungicide.

Castor Cautions

If you have dogs that chew on plants, do not plant castor. It can “unalive” them.  Choose from other pet friendly plant options.

Do NOT plant castor too close to your fish pond if you have one.    Fallen leaves or seeds could kill fish.   

You can compost the leaves and stems though.    Once well composted they pose no hazard to humans or animals.

Harvesting and Use   

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!

More about the ethnobotany of castor in a future post – I hope. There are more topics that days! Uses of castor will be on Savor the Southwest at some point, because it is one of the many “Father Kino Herbs.”

Happy Growing!
Jacqueline

Castor is a Kino Herb!

The last few copies of this out-of-print award winning Southwestern book are now for sale. Father Kino’s Herbs: Growing and Using Them Today   The review says:

“Award-winning garden writer Dr. Jacqueline A. Soule has pulled together a fascinating book on the life of Father Eusebio Francisco Kino and some of the plants that he brought to Southern Arizona and northwestern Sonora, and area called the Pimeria Alta.”

This link is to our sales site. The profits from the sale go to the local Horticulture Therapy non-profit Tierra del Sol Institute.  We hope you will help support this great Southwest non-profit!

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Disclaimer

The authors of this website have researched the edibility of the materials we discuss, however, humans vary in their ability to tolerate different foods, drinks, and herbs. Individuals consuming flowers, plants, animals or derivatives mentioned in this blog do so entirely at their own risk. The authors on this site cannot be held responsible for any adverse reaction. In case of doubt please consult your medical practitioner.