This week we are dealing with a real oddball. The Mystery Plants featured in this column are usually native species here in the Southeast, although every once in a while we’ve offered a curious cultivated plant. Like this one.

Ghost Plant, Graptopetalum paraguayense, is one of the best examples of a succulent plant that you could ever come up with. It is not at all related to any cactus, although cacti, too, exhibit succulence as a growth “habit.”

Succulence in plants is not at all restricted to any one group of species; rather, the attribute of succulence, or the tendency to store water in variously swollen plant parts, is just one more way in which different species have adapted to special habitats, in this situation, arid and dry ones.

It should seem obvious that many (most?) plants that exhibit the highest degrees of succulence should come from deserts or similar kinds of places. Anyway, there is no such thing as “the succulent family.”  So don’t use that phrase. 

This plant has achieved a reputation, over the last century, as one of the easiest ornamentals to grow. The plants produce cylindrical stems bearing, towards their tips, roundish clusters, or “rosettes,” of leaves. The leaves are peculiar in being very fleshy and thick, somewhat triangular, and pointed.

The leaves are quite attractive, and depending on how much sun they get may develop a beautiful blue-gray sheen, or sometimes a dusty white look, from a thin layer of wax on the surface.

Being fully drought tolerant, they make terrific additions to dry rock gardens, and can be grown in pots. If the pots are attached to a sunny wall, the stems eventually spill over, which is a nice effect, too.

Blooming occurs in the spring (which was when this photo was taken). Star-shaped, white or yellowish flowers are produced on slender stalks that arise from just below the leaf rosettes. The plants love sandy, gritty, thoroughly draining soil. Mine seem to thrive on inattention. I can’t even remember where I got these; they seem to have been around forever.

If you have some of these plants in a pot, and you start fiddling around with them, you’ll quickly discover that the leaves are brittle, and will easily break off the stem. Each detached leaf will sprout, forming a “new” individual, and so it is no wonder that this plant has a sort of “hand me down” reputation amongst gardeners.

This species is closely related to the various varieties of Sedum, which are also succulents, but botanists generally classify our Mystery succulent within its own group of species.

Its history is interesting. For the longest time, it was known only from cultivation, growing in a greenhouse that featured a number of cacti. Some of the plants growing with it were from Paraguay, and thus it was assumed that this one was, too. Its scientific name thus suggests that it IS from Paraguay, but it’s not.

It is known now to occur, in the wild, only in Mexico. Nevertheless, the Paraguayan name must stay with the plant, due to the rules of botanical nomenclature.  

John Nelson is the curator of the A. C. Moore Herbarium at the University of South Carolina, in the Department of Biological Sciences, Columbia SC 29208. As a public service, the Herbarium offers free plant identifications. For more information, visit www.herbarium.org or call 803-777-8196, or email nelson@sc.edu.