Disas are indigenous to tropical and southern Africa, with a few more in the Arabian Peninsula, Madagascar and Reunion. Disa bracteata is naturalized in Western Australia, where the local name is ‘African weed-orchid’. Disa uniflora is the floral emblem of Cape Province in South Africa. They are terrestrial and grow along the banks of streams and other wet areas at altitudes between 100m to 1200m. The one most commonly grown in Tasmania is Disa uniflora. Colours can vary from brilliant orange, bright pink and yellow. The genus Disa was named by PJ Bergius in 1767 and was named after Disa, the heroine of a Swedish legend.
CONDITIONS: Protect from heat. They can tolerate temperatures near freezing and can be grown outside in the garden in a shaded area. If grown in a shade house, provide ample air movement and humidity.
POTTING MIX: Sphagnum moss is ideal, but if not available, a general potting mix with added coarse sand and perlite can be used. The mix should be free- draining and not mud-like.
WATERING: Disa require more water than most orchids. Keep wet at all times through Summer and ease off during Winter, but always towards the wet side. Pure rain water is preferred. If not available, fill a container with tap water and leave sit for a day before using.
FERTILIZING: Apply soluble fertilizers at ½ strength, as well as seaweed based food. It is best to under feed rather than over feed.
FLOWERING: Flowering is from Spring until mid-Summer. Flowers appear on last year’s growth, which grows from a tuber. This growth will die after flowering. During flowering the tuber produces more tubers and small plants will appear and become the future flowering growths.
REPOTTING: After the flowering growth dies, gently divide the new growths. The roots are very brittle so take care in handling them. If grown in Sphagnum moss, re-pot yearly. You can allow several years between with other mixes.
PROBLEMS: White mealy bugs and aphids can be a problem. Treat with a commercial pesticide such as Eco Oil. Slugs and snails should be fed with snail bait. Drying out in hot weather as well as becoming water logged over long periods will also place stress on the plant.