Habitat: Tropical belts of central and southern Africa.
Cultivation: the caudex should be protected from direct sunlight (in its natural environment it is often buried) but branches and leaves tolerate more exposed positions. It is particularly sensitive to cold: never keep it below 10°C.
Curiosity: The name “Gerrardanthus” was chosen in honour of William Tyrer Gerrard, a botanist and plant collector who lived and worked in the South African province of Natal and in Madagascar around 1860.
The genus Gerrardanthus consists of perennial climbing plants with a large tuberous caudex at the base. They belong to the same family of pumpkins!
These plants usually grow as vines climbing other trees or creeping at ground level, also among boulders and stones, in moist, shaded areas.
In their natural habitat, the caudex is often buried (partially or almost completely) and can reach an impressive size: up to about one metre in diameter! It shows a corky, irregular surface. The caudex is an evolutionary device typical of plants native to dry or semi-dry areas, namely with an alternance of dry and humid periods.
Above the caudex the stem thins out very quickly and branches, which can be up to 5 metres long, grow from it.
Palmate, triangular-tipped leaves sprout from the stem. They are green in colour but show a beautiful silvery sheen, reminding the more common ivy. The leaves fall off in winter and are replaced the following spring, as Gerrardanthus is a deciduous species. From the leaf axis, many coiling tendrils are produced.
Flowers are generally inconspicuous (they don’t exceed 2 centimeters in diameter) and the plants are usually monoecious or dioecious. In both cases, we can find male and female flowers: monoecious means that, in one plant, there are both male and female flowers, while, on the other hand, dioecious means that male and female flowers are present in different plants, resulting in “male” and “female” plants. Male and female inflorescences are also different: male flowers are usually grouped in a raceme (a cluster, in “botany language”), while the female ones are solitary.
Flowers, moreover, are generally star-shaped, with five greenish-brownish, triangular petals. Usually, the growing season occur between January and March, when, in the southern hemisphere, it’s late Summer.
Seeds are very small and develop in capsules (a capsule is, in botany, a particular kind of fruit). Their small dimension, along with their wing, allow them to be dispersed by the wind.
Some species of Gerrardanthus, such as G. macrorhizus, show some kind of medicinal properties, as they were used as purgatives for pregnant women.
VARIETY AND TYPES
Gerrardanthus are rather rare succulents, especially in trade. The easiest species to find, however, is definitely G. macrorhizus, also called ‘bigfoot’ because of its impressive size. Here is the complete list of species.
- G. aethiopicus
- G. grandiflorus
- G. lobatus
- G. macrorhizus (bigfoot)
- G. nigericus
- G. paniculatus
- G. parviflorus
- G. portentosus
- G. tomentosus
- G. trimenii
- G. zenkeri
TIPS FOR GROWING
Here are our cultivation tips:
The caudex should be protected from direct sunlight (in nature, it is often buried) but branches and leaves can withstand it. A safer solution is to place it in a bright area without direct sunlight, or in semi-shade.
It is particularly sensitive to cold: never leave it below 10°C, not even in winter.
Water abundantly during the vegetative season (spring and summer). In winter reduce the frequency of watering and leave the plant completely dry during the winter rest.
Choose a well-draining and moderately fertile soil. For example, a 50% mix of peat and inorganic material (perlite, etc.).
Fertilize during the growing season every month, using a fertilizer for green plants but in half the dose indicated on the package.
Gerrardanthus grows very quickly and you will notice by the rapid enlargement of the caudex. Repot in early spring, taking care not to damage the stems and branches, which are light and delicate.
Gerrardanthus are propagated exclusively by seed. Branch cuttings take root, but the seedlings thus generated cannot recreate the caudex.