Alan W. Meerow
For the past three years, Eucrosia bicolor var. bicolor (Amaryllidaceae), a tropical bulb native to Ecuador, has been evaluated for landscape performance at the Ft. Lauderdale REC, while its utility as a cutflower crop has been investigated by Dr. Mark Roh of the USDA and the author.
Flower stems are about 2 feet tall and bear 6-10 red flowers with long, curved yellow stamens. Each individual bulb remains in flower for about 2 weeks, but as large clumps are rapidly formed, total bloom period will extend upwards to a month. The bulbs generally get no larger than 1 and 3/4 inches in diameter, but are capable of flowering when they achieve a minimum weight of 25 grams (Roh and Meerow, 1992; Roh et al., 1992).
The attractive leaves of eucrosia are light green and elliptic in shape with short stems. Each bulb produces 2-3 leaves. A flowering size bulb produces 2-4 offsets every year, as well as several smaller bulbils. A bulbil with a minimum fresh weight of 5 grams will grow to flowering size in one season of growth (Roh and Meerow, 1992).
In the landscape, eucrosia is a spring flowering bulb. Inflorescences appear shortly before leaf emergence, usually in April. In the landscape, eucrosia is best situated in partial shade. Full sun beyond noon will bleach and possibly burn the leaves. The bulbs will grow in any well-drained soil, and should receive periodic fertilization with a complete landscape blend.
In October or November, the leaves of eucrosia will begin to yellow, indicating the onset of dormancy. At this time, maintaining the bulbs dry will insure maximum flower initiation, though periodic irrigation during the winter months has not resulted in either suppression of flowering or loss of the dormant bulbs in ground beds at the Ft. Lauderdale REC.
Information on production and forcing procedures for eucrosia can be found in Roh, 1991.
Roh, M. 1991. Eucrosia for cuts. Greenhouse Grower 9(9): 100-104.
Roh, M. S. and A. W. Meerow. 1992. Flowering of Eucrosia as influenced by bulb weight. HortScience: 1227.
Roh, M. S., K. C. Gross, R. S. Lawson and A. W. Meerow. 1992. Flower bud initiation and development of Eucrosia bicolor as influenced by bulb storage temperatures. Acta Hortic. 325: 105-111.