A Rough Character
The idea of "Jewels" encompasses delicate, exquisite beauty and great value. Paradoxically, this particular Jewel looks and feels as though it is ready for harsh, rather than royal, treatment. This plant is available commercially under the name Alocasia rugosa, but the accurate scientific name is almost certainly A. melo. This "Rugose Jewel" is endemic to Sabah, Borneo, and was first described as A. melo in 1997. Specimens grown for the horticultural market are produced from tissue culture plantlets or more rarely, from offsets or corms, not seedlings.
The descriptive term "rugosa" refers to the distinctively rugose (wrinkled) and bullate (knobbly, puckered) leaves (see photo detail, left). The overall look of the plant indicates that it grows under conditions where drying out is likely. In fact, the native habitat of this plant is the rain forest. However, in the rain forest it is found growing in rock crevices and on thin soil along steep banks of fast flowing streams. So while high humidity is the norm, high aeration to the root zone is also the norm. On days when rain falls scantily or not at all, one can easily imagine this plant drying out on those steep banks or in the rock crevices. This information is valuable because it tells the would-be jewel grower what type of conditions are likely to lead to success in growing this Rugose Jewel.
High and Dry?
Your first consideration is to provide high humidity and moderate light for this plant. The native habitat described above would indicate that exposure to full sun is infrequent. During parts of the day, the plant is probably in deep shade under overhanging foliage. The next consideration is the soil medium, which must be very loose and fast draining to keep a high level of aeration to the root zone. I've had success growing these plants by allowing the medium to become almost completely dried out between waterings. A good soil medium should contain a minimum of peat, and ample amounts of washed Perlite, silica sand, and just enough composted organic matter to hold some moisture. Fertilization should be light but regular, and with that regimen, your Rugose Jewel will grow surprisingly rapidly.
These plants are amazingly intolerant of too much moisture. My first specimen, for which I paid dearly, become submerged briefly after a big storm. Even after being rescued and dried, the plant promptly succumbed to total rot. Nothing I could do would reverse the extreme shock the plant went into. The lesson is that you should never allow your Rugose Jewel to become waterlogged, even for just a few hours. This means, of course, that you have to keep your plant out of the rain and under cover. By the way, this is a good rule of thumb to use when growing any of the Jewel Alocasias.
Where can I get one?
These plants can sometimes be found at specialty nurseries or garden centers in the Spring, especially if the store specializes in exotic tropicals. I know of one wholesale grower who produces a lot of these plants and ships them all around the country to nurseries and garden centers. The Garden WatchDog shows one nursery, Green Sunshine, that lists this plant as available. Rugose Jewels do not grow very large and can be maintained in a 6" pot for several years. After that time, you should have several plants in the pot. If you are quite confident about your Jewel growing ability, you can try separating them and growing on the little corms you find when you unpot your plant. These Jewels are interesting to own, fun to touch, and easy to keep if you remember to keep the soil on the dry side most of the time.Photo credit: LariAnn Garner, Aroidia Research