Monadenium (2017)

By Bob Williams (October 2017)

I have a Monadenium ritchiei in my collection that has been good to me. This is one of the first plants I bought after I joined HSCSS. That should give you an idea that this is a hardy plant. It has filled the pot nicely with a symmetrical mound. I also received a blue ribbon this year for this plant. Right now it is in full flower.

I see a plant full of small, pinkish flowers on my patio every morning. Everything is good until you decide to research monadeniums. A monadenium is not really a monadenium. Depending on the source, it is a euphorbia or part of a genus within the Euphorbiacae family.

Monadenium is a genus of about 50 species related to Euphorbia. Almost all the species are native to tropical East Africa. A large number are found in Kenya and Tanzania. Most grow at elevations from 2,000 feet to 3,500 feet. They grow in grasslands and savannah settings, and a few are found in dryer forests.

The common denominator for these plants is that they grow in a dry climate. From my research, the flowers for most of the plants are small and pinkish. Like euphorbias, the size of monadeniums can border on the extreme. Some plants only grow to 6 inches, while a few can grow to 10 feet or more.

Growing monadeniums is not very difficult. They can take direct sunlight and thrive in bright, indirect sunlight. A unique thing about monadeniums is that if they are grown in direct sunlight, the leaves and body will turn reddish. If they are moved to a very bright indirect light, the leaves and body become dark green.

As with any succulent, a well-draining mix is recommended. Monadeniums can tolerate a little extra water before rot sets in, but you should water when the mix is close to dry. These plants are not winter-hardy in this area, but at higher elevations in Africa, they can tolerate temperatures in the low 40s.

Propagation can be by seed or cuttings. In all of the research I conducted, cuttings seem to be easier. Like euphorbias, these plants have the white sap that can cause issues. Care should be taken when propagating by cutting or trimming the plants.

Monadenium ritchiei is the most common plant found in cultivation. It only grows to a height of 10 to 18 inches. This plant grows thick, knobby segments. These segments can be 1 to 1.5 inches in diameter and 3 inches long. As I said earlier, this plant is easy to grow. It spreads by underground shoots and forms large clumps. When choosing a pot, a wider than normal pot should be considered. You may find that you need to repot this plant more often than others.

There is one monadenium that is favored by bonsai enthusiasts, the succulent crowd and those who like hanging plants – M. rubellum. This plant is found in Kenya, growing in rocky soil at elevations of 4,000 to 5,000 feet. In habitat, the tuber is completely underground.

The unique thing about this plant is that the stems growing from the tuber are much longer than those of other species. They can be 1 to 2 feet long. As the tuber grows bigger, the plant grows more stems. I found pictures of a plant with nearly 20 stems hanging from the plant. The leaves and stems will turn reddish if placed in full sun.

This plant prefers a lot of light, but not direct sunlight. In deep shade, it gets weak and leggy, and eventually rots. Water during the growing season, from spring to fall. Give it a little extra water when in flower.

During the winter, the leaves and flowers will fall off. Cut back on the water when this happens, and keep it fairly dry. This is the time when just a little too much water can cause rot. M. rubellum can be propagated easily by stem cuttings. A caudex will be created with a stem cutting.

For the bonsai enthusiasts among us, the tuber is key. The tuber does not grow very big, maybe 6 inches across.

This plant doesn’t seem to grow in a “ball,” but seems to send out a number of roots that grow very fleshy and “gnarly.” Most articles I have read suggest the tuber stay totally underground for over five years before raising the caudex. A 5- to 8-year-old caudex will be around 6 inches across. This is not a fast-growing plant.

Monadeniums can be found for sale fairly easily from the usual vendors. However, very few – maybe 10 – of the 50 species within the Monadenium genus are typically available. Give them a try, though. If you have five to 10 years, give M. rubellum a try. The wait will be worth it.