Sinningia speciosa hybrid
Photo by Gustav Ciamaga.
The modern hybrids of S. speciosa bear little resemblance to the ancestral species. These "Florist Gloxinias" (no close relationship to the true species Gloxinia) are very large-growing (sometimes exceeding eighteen inches in diameter), with spectacular richly coloured flowers in the center of the rosette.
The large-growing forms available at nurseries and florists are not easy to grow well under home conditions, although it can be done. A better choice for the home grower are the more compact-growing forms, which are available as seed from a number of sources, including the various gesneriad plant societies.
The "Florist Gloxinias" prefer good light, and a moderately warm and humid location. They should be kept evenly moist, given regular fertilizer (perhaps as much as 1/2 tsp per gallon of 20-20-20 with every watering, during the period of fastest growth and flowering), and protected from insect pests. When they finish flowering, the plant should be maintained with less fertilizer until it begins to go dormant. At that point, the foliage can be discarded, and the tuber repotted or kept in its original pot. When growth begins again, the tuber should be potted up in fresh soil.