Culture
Hardy in frost free Zones 11-12. Suitable as a houseplant or greenhouse plants outside the subtropics. They need a steady temperature, not necessarily hot, but average to warm, dappled light and shelter from cold drafts. Allow to dry somewhat in winter. Avoid wetting foliage when not in active growth, less watering for 6-8 weeks often stimulates best flowering. When in active growth, keep the soil moist and water with tepid water. Give the plants constant, fairly high humidity. The plants require well-drained soil and moderate fertility.
Noteworthy Characteristics
Columnea microcalyx, commonly called goldfish plant, has trailing stems with rounded oval hairy leaves ranging from green to reddish-brown and orange-red flowers with a yellow throat. They have slightly arching pendulous stems that form a crown of foliage. They are almost always grown in a hanging basket to display their trailing flower stems.
Genus name honors Fabius Columna (Fabio Colonna, 1567-1640), author of the first botanical book with copper-plate illustrations, published in Naples 1592.
Specific epithet means small calyx.
Problems
Problems include botrytis mold, fungal leaf spots, mosaic virus, aphids, spider mites, and whiteflies. Leaves drop due to drafts and low humidity. The leaves may also brown from a build up of calcium in the soil.
Uses
Almost always used in hanging baskets to effectively display their flowers.