Trochomeria (2018)

By Bob Williams (June 2018)

The next group of plants on my caudiciform journey is from the Cucurbitaceae family. This is a very large family. Depending on the source, there are from 90 to 125 genera, with a total of 700 to 850 species.

Cucurbitaceae is also called the gourd family. Squash, gourds, cucumbers and watermelon are some of the fruits from plants found in this family. Plants in this family have been cultivated as a food source for thousands of years and in all parts of the world.

A few genera within Cucurbitaceae are of interest to the succulent and fat plant growers among us. Cephalopentandra, Coccinia, Coniandra, Ibervillea, Momordica and Odosicyos are a few. To see a more comprehensive list, visit the Llifle Encyclopedia of Succulents at https://www.llifle.com/Encyclopedia/SUCCULENTS/.

These plants produce some interesting caudices and may be of interest to members of our group. One genus you will not see is Trochomera! I don’t know why. I can tell you this: there is very little literature on growing Cucurbitaceae succulents. One of the most comprehensive articles I found was written in 2001 for the Central Arizona Cactus and Succulent Society newsletter as a “plant of the month” – http://centralarizonacactus.org/assets/newsletter/2001/CACSS_Newsletter_Central_Spine_2001_06_June.pdf.

Trochomeria was a late choice in my grand experiment. I was searching images of caudex plants, and one image called my name. The caudex was gnarly and twisted, like this author. Trochomeria debilis was the plant, and as luck would have it, Grigsby Cactus Gardens has a supply for sale.

There are nine recognized species in Trochomeria. All are found in Africa. None of the species has a very large range. T. debilis is found in Botswana and a small area of South Africa. It was first described by George Bentham and Joseph Dalton Hooker in 1867. It must not have made a very good impression, because “debilis” is derived from the Greek meaning weak, frail and feeble.

The caudex of T. debilis will grow up to 10 inches in diameter. In the wild, the caudex is completely underground, where it serves as water storage. During the growing season, the plant grows very long vines that can reach 10 feet in length. When growing T. debilis in your collection, a trellis may be needed. I would imagine the vines are not very sturdy due to the name of the plant. The plants produce both male and female flowers. The fruits are small and orange-red in color.

From what little I found about growing succulent Cucurbitaceae, it doesn’t seem hard. Propagation is almost always from seed. One site said, “If you can grow zucchini, you can grow succulent Cucurbitaceae.” We will have to see about that.

As with any caudex succulent, T. debilis should be grown in a well-draining soil mix. Water when the soil starts to dry in the summer and cut way back in the winter. The plants tend to be slow growers. Raising a plant with a 10-inch caudex will take time.

Periodic fertilizing during the growing season will help. Some sites say these plants do better in filtered sunlight rather than direct sun. They can withstand high temperatures. During winter months, they can take temperatures in the low 40s, but not much lower.

One thing you need to worry about is insect damage. Squash vine borers, squash bugs and cucumber beetles can be very big problems. All of the literature on insect damage is about control and vegetable crops, but I am sure the problem is the same for the plants we grow.

These pests lay their eggs in the soil in late fall, and their larvae attack plant roots during the winter. A good systemic insecticide is recommended. Pam Schnebelen told me she has information about these pests and will most likely expand on what little I wrote here.

When looking for information, I stumbled on a most interesting website, The Biodiversity Heritage Library – https://www.biodiversitylibrary.org. The website says the library is “a consortium of natural history and botanical libraries that cooperate to digitize the legacy literature of biodiversity held in their collections and to make that literature available for open access and responsible use as a part of a global ‘biodiversity commons.'”

The BHL consortium works with the international taxonomic community, rights holders and other interested parties to ensure this biodiversity heritage is available to a global audience through open-access principles. BHL has digitized over 120,000 titles and 200,000 volumes.

You can search by plant name, and the system returns results listing all printed references to that plant that have been digitized. Much of the literature dates back to the late 1800s. You can read what the early botanists wrote here. The Missouri Botanical Garden is a member of this library.