Gloriosa is a small genus of climbing vines in the Colchiaceae family known for their brightly-colored flowers. The plants are deciduous perennials and go dormant over the winter. More commonly known as the gloriosa lily, these plants grow from a tuber and form vines 3 to 8 ft (0.9 to 2.4 m) tall. All parts of the plant are poisonous, especially the roots. The plants are rampant weeds in parts of Australia.
Cultivated plants are usually a variety of Gloriosa superba and are typically grown as houseplants and greenhouse plants. They are also grown in the garden year-round in tropical and sub-tropical climates, such as that of Australia. Within the United States, they are grown as deciduous perennials in warm regions, like Florida. In cooler areas, they are placed out in the spring for summer bloom. The tubers are then usually brought inside for the winter.
Gloriosa lily vines climb by tendrils at the tips of 5 to 7 in (12.5 to 17.5 cm) leaves. They grow well on trellises. Some gardeners let them scramble over shrubs. The 4 inch (10 cm) flowers that are borne on top of the vines are striking with six lobes of bright red banded with yellow. The colors may vary, depending on the variety.
The tubers should be planted in a location that is partially to fully sunny. Soils with a lot of salts should be avoided. Some experts advise planting the tuber directly in the ground, flat side down in a 2 inch (5 cm) hole. Others suggest leaving the tuber in an 8 inch (20 cm) pot and planting the whole pot in the ground.
After the plant has finished blooming, one should cut back on the amount of water. Also, following the first light frost, the foliage should be trimmed from the tuber. These can be brought inside over the winter for protection against cold weather. They should be stored in dry sand or peat moss. Advice on the proper storage temperature ranges from 35-65°F (1.7-18.3°C).
As houseplants, gloriosa lilies prefer direct sun. The soil should be kept moist. While flowering, fertilizer should be added at two-week intervals. Ideal temperatures are 65-70°F (18.3-21.1°C) at night, and at least 75°F (23.9°C) during the day. The plants should undergo a rest period similar to that of plants grown outside, except that they can be left in the pot. This period of dormancy is usually from October to January.
The toxicity of these plants is due to the presence of the alkaloid colchicine. This chemical is used by plant breeders and is harmful to animals, including humans. Despite this, the plant is used as a medicinal plant in India and Africa — in fact, in Zimbabwe, the national flower is Gloriosa superba. Harvesting of the plants for use as a medicine has caused the native populations in some areas to greatly diminish.