Trichodiadema (2018)

By Bob Williams (March 2018)

The genus Trichodiadema is a member of the Aizoaceae family. Some members of this large and diverse family include Aloinopsis, Conophyllum, Delosperma, Lithops, Mesembryanthemum, Nananthus, Rabia and Titanopsis. Just looking at a few of the plants in these genera reveals a few things about Trichodiadema.

First, they do not grow very tall. The maximum height for the largest Trichodiadema species is 12 inches. Most are in the 3- to 6-inch range.

Second, these plants grow low to the ground and spread out. The largest Trichodiadema species have diameters up to 12 inches when fully grown. Most are half that size.

For the home brewers and cooks in the crowd, this plant group is for you. Roots of some species of Trichodiadema have been used in the past to speed the fermentation of bread, beer, etc. The roots contain yeast or sugars that increase the rate of fermentation.

The name Trichodiadema comes from the ancient Greek “trikhos,” meaning hair or bristle, and “diadema,” meaning crown. The genus Trichodiadema, comprised of around 30 species, is found in southern Namibia and in the Northern, Western and Eastern Cape Provinces in South Africa.

By looking at where these plant grow, we know that high heat, bright sun and sparse rainfall are the norm. We also know that in order for them to survive, water will be stored in the roots – creating a good-looking caudex.

Trichodiadema bulbosum grows in the Western and Eastern Cape regions of South Africa. This is also described as the Port Elizabeth region. In 1814, this plant was given the name Mesembryanthemum bulbosum by Adrian Hardy Haworth. It was given the name Trichodiadema bulbosum by Martin Heinrich Gustav Schwantes in 1926. This is the currently accepted name.

T. bulbosum is one of the larger plants in the genus, growing to a height of 12 inches and branching out to a diameter of 12 inches. The leaves are many but small, with each leaf about one-eighth inch wide and no more than one-half inch long. The leaves have a light waxy coating. For these plants, water conservation is key.

This plant has attractive flowers that range from violet to purple red with a yellow center. In comparison to the size of the leaves, the flowers are very large. Flowers can be from 1 1/2 to 2 1/2 inches in diameter. Even if you don’t want to grow T. bulbosum for the caudex, grow it for the flowers. Another plus: This plant will flower all summer long, from late spring to early fall.

Trichodiadema bulbosum is a popular bonsai plant among bonsai enthusiasts. Over time, the caudex will expand to the diameter of the plant. This means if I do everything right, and the plant likes me, I could have a twisted, knotty caudex in the 8- to 12-inch-diameter range.

Care for the plant should reflect the basic care practices for other plants found in the hot and dry regions of Western Africa. The soil mix should drain well and contain some grit. Care information from some sources suggested that a soil mix with a small amount – no more than 10 percent – of organic matter works best.

T. bulbosum should be watered well during the growing season. Every source said to not let the soil mix dry out during this period. The plant can tolerate high heat and bright, direct sunlight. Some sources said better growth can be attained by giving the plant direct morning and afternoon sun, but bright indirect sun during the heat of the day. I am not sure how you do that. This plant can take a light frost, but is not cold-hardy in our area.

It is fairly easy to find these plants for sale on the Web. You may also find them at your local Walmart under the common name of “ice plant.”

Note: As announced in January, Bob Williams is embarking on an experiment to see if pot size affects caudex growth. He will raise plants of the same species and size under the same conditions for three growing seasons, but vary pot size. Trichodiadema bulbosum is the first test species. The plants’ caudices will be compared in the spring of 2021.

Sources:
Succulent Gardening – http://www.succulents.us/trichod.html
LLifle Encyclopedia of Succulents – http://www.llifle.com/Encyclopedia/SUCCULENTS/Family/Aizoaceae/