Dioscorea rupicola is another beautiful, weird and wonderful, caudiciform plant. It too, has a deeply fissured surface, resembling a turtle's back, but will only grow one vine that can reach up to 8 meters in it's growing season. It makes a most interesting container plant.
Dioscorea rupicola is summer deciduous and is a perennial geophytic climber. In summer the leafless plant conserves energy by dropping its leaves in October, just before the onset of the summer heat. The plants are monoecious, that means the flowering sexes are found on separate plants. The stems grow in a climbing fashion. The leaves are heart-shaped. Male flowers are erect with spiny racemes. Female flowers are in spinescent, spreading spikes. Flowers are pale green and normally appear in May or June. Seed is produced in September and October.
The plant appears to have a wide tolerance of growing habitats, growing in weathered rock, on dry, stony slopes, under the protection of karroid bushes. The plant's caudex (short, thick stem) can reach heights of 3 m in ideal conditions.
Dioscorea rupicola will live for approx. 80 years in cultivation, if it is looked after correctly. Remember it drops its leaves iate November. Do not over-water during the summer months, as this will shorten its life span by at least half. Dioscorea rupicola needs a rest period. In its natural environment it rests during the hot dry summer. Dioscorea rupicola grows in the winter and the spring months.
Above: The above ground caudex of a 3 year old seedling.
It is believed the Khoisan used to bake the starchy, bread-like trunk which was used as a food source. Other members in the genus Dioscorea are used to extract steriodal saponins which are used to produce cortisone and and contraceptives. Many of the South African species have been over-harvested for testing purposes.
Pollination is done by bees and bumble bees. The plant is adapted to growing in areas with seasonal rainfall, by going dormant in the dry season. The above ground caudex is protected by elephantine bark while it rests.