Monsonia (2014)

By Eric Driskill (February 2014)

Monsonias are members of the Geraniaceae family. Pelargonium is another genus in the Geraniaceae family with xerophytic species found in succulent collections. Linnaeus described Monsonia in 1767. Over the next 247 years, this genus was moved between Sarcocaulon and Monsonia.

Plants in the genus interesting to succulent growers are small, sometimes annual, and herbaceous, occasionally with somewhat tuberous roots. These plants endure in some of the most desolate winter rainfall regions in Namibia and South Africa.

The plants regularly survive extreme drought conditions, aided by the thickened stem cortex impregnated with resin and wax, which form an impervious layer. This makes them highly flammable, a characteristic that earns monsonias the name “boesmankers” or bushman candles.

Monsonias grow from southern Angola on the west coast down into Namibia, across open karoo rocky areas, all the way to the Great Fish River valley in the Eastern Cape. The plants are leafless for most of the year, at times remaining leafless for several years at a time.

They come in two forms. One form has reduced, simple ovate leaves and very spiny stems. Horizontal branches are suspended an inch above the soil on stout stems. Species include pink-flowering species M. patersonii and avranii; yellow-flowering species, M. iliata, flavescens and spinosa; and white-flowering species, M. crassicaule and vanderietiae.

The other form is mostly spineless and branches differently. These plants have strange horizontally growing stems shaped like tiny deep-keeled boats. Most of the spineless monsonias have extremely tight, finely dissected, fern-leaf foliage, often covered in fuzz. The species in this form are all found in the intensely arid regions of the Richtersveld and nearby southern Namibia. Species in this form include M. peniculinum, multifida, herrei and inerme.

A little water during their dormant period will not hurt them. The best rule of thumb is to water them sparingly when in full growth and pass over them with your watering can when their foliage drops until it starts up again. A very porous, free-draining soil is recommended.

Plants of the first form may be propagated either by seed or cuttings, but the second form is almost always grown from seed. This may certainly explain the availability of plants in each form.

Sources:
Succulent Flora of Southern Africa – Court, Doreen — 2010
The Timber Press Guide to Succulent Plants of the World – Dortort, Fred — 2011