HOW I GROW PROMENAEAS by Rex Johnson
Native to central and southern Brazil, the genus Promenaea comprises a number of delightful, small plants that are easy to grow at intermediate temperatures and in partial shade. Some growers seem to have trouble maintaining them in cultivation. However, we have found that promenaeas grow well provided that they are kept rather dry during winter. If kept wet at this time they tend to lose their roots and then fail to re-establish when warmer weather arrives. Given successful culture, even small plants of two or three bulbs will flower, and larger plants in 80 mm pots may produce as many as twenty or thirty flowers.
Of the 14 species in the genus Promenaea, only a few are in general cultivation. However those species and their hybrids presently available have very attractive flowers, ranging in colour from the clear bright yellow of P. xanthina to the near purple of some hybrids of P. stapelioides. The flowers average about 55 mm across, those of the hybrids being well filled-in, most of them with nice broad lips. The flowers are usually displayed on 60 mm spikes that support them clear of the foliage, often around the rim of the pot so that they form an attractive ring of colour. Each pseudo-bulb (25 mm tall) carries two pairs of leaves, one from the apex and other at the base. Well-developed pseudo-bulbs produce two inflorescences from inside the pair of basal leaves. With luck, some inflorescences bear two flowers, thus adding to the floral display. They last three or four weeks, provided that the weather is cool and that the plants can be held in a cool spot.
Being epiphytes, promenaeas need a free-draining potting mix, so we use small, composted pine bark (5-8 mm) containing a little shredded Sphagnum moss. Because moss does not like chemical fertiliser, we use only organic fertiliser, and apply it only in warm weather during the growing cycle.