I have tried to grow several weird and sometimes attractive succulents over the years, and though most end up being disasters, some actually grow well for me. The subject of this article is Xerosicyos danguyi, or the Silver Dollar Plant, a drought tolerant vine from Madagascar with surprising hardiness in our Mediterranean climate here in Southern California.
Xerosicyos danguyi growing in botanical garden with other Madagascan natives
The genus Xerosicyos has at least three species in it, all native to southern Madagascar. They are in the family Curcubitaceae, the cucumber family. The name Xerosicyos actually means dry cucumber. Though all three species are caudiciform vines, Xerosicyos danguyi is mostly vine and very little caudex. The other two species, Xerosicyos pubescens and Xerosicyos perrieri, are deciduous in the dry season, but this plant seems to retain its thick, circular, succulent, flattened, pale green leaves all year round (the leaf shape and size gives this plant its common name, though they are not silver in color). All these plants are basically wet-weather growers and seem to flower in the winter to early spring. All Xerosicyos are dioecious (two different sexes). Flowers are tiny and pale yellow, and look like little origami boxes before they open up.
Xerosicyos danguyi in my yard (left) close up of foliage and vine tendrils
early 'box-like' unopened flowers (left) flowers starting to open up on my own vine (right)
flowers fully open in mid to late spring
Xerosicyos danguyi is a fairly fast growing plant, covering surrounding vegetation in just a few years, using its little winding tendrils to grab onto things and help support the weight of this relatively heavy vine. This plant grows pretty well in my dry climate in southern California, but seems to do very well in the wet Florida climate, too. It takes mild frosts (at least here, though I cannot say exactly how cold it will survive as it has not been well tested yet in my yard). Soils should be pretty well draining, but I find that if they are too well draining, it struggles and actually seems to like water much of the year. It tolerates pretty high heat, but the leaves facing the sun on their flat surfaces do scorch a bit if it gets over 100F. Many in cooler climates grow this plant in hanging baskets and keep it indoors most of the cooler times of the year. I have not tried that myself. Propagation is reportedly fairly easy from cuttings, but I have yet to try that, either. But overall for a ‘weird' plant, this one is surprisingly easy to grow. If you see this little gem for sale at a cactus/succulent show, you should consider trying it out.
Vines growing over surrounding vegetation in these two souithern California gardens
look of young vine growing against a wall and climbing it (left); plant in Los Angeles Arboretum growing out in open without any vegetation to grow on (right)
The other two species of this seem a tad more tender though I have no personal experience with either. Both develop very large caudeces and older plants can be quite pricey. The leaves of Xerosicyos perrieri are thick and succulent as well, but a darker green and more ovoid than those of Xerosicyos danguyi. Xerosicyos pubescens has more typical leaf shape and texture (somewhat fuzzy, actually), and are what some call ‘semi-succulent'. The caudex of this species can reportedly grow to enormous proportions. This latter species is sometimes under the genus Zygosicyos instead of Xerosicyos, but I am not sure what the final correct genus is at this time.
mature Xerosicyos perrieri (left photo mgarr) seedling Xerosicyos perrieri (right photo lazerpherine)
Two show plants in Los Angeles of Xerosicyos pubescens
sale plant at a Los Angeles show (pricey!)