This genus includes about fifty species of terricolous orchids, originating from the Australian continent, with deciduous leaves. They have large tuberous, oval or palmate roots, from which 3-4 or longer thin, ribbon-shaped, green leaves depart, 15-30 cm long, flexible, similar to long blades of grass; in autumn they produce a long stem, which bears 3-9 large flowers, of golden yellow color, with streaks or brown or purple dots, with the labellum darker than the rest of the flower. Many species of diuris are endangered, and are only rarely grown by amateurs.
These orchids are a deciduous variety with a shrub bearing, as their tubers tend to spread in the ground; for pot cultivation it is therefore advisable to choose large containers.
The Diuris prefer semi-shaded, well-ventilated places; do not fear the cold, but generally do not like excessive heat, usually in the summer months they go into vegetative rest. With the arrival of summer the aerial part dries up and then grows again in the autumn period. For their cultivation it is good to plant them in a place where they do not receive direct sunlight, especially during the hottest hours of the day, which can quickly ruin the leaves.
From October to May water regularly, letting the soil dry a little between watering and checking that water does not form in the soil, which can lead to root rot. In the remaining months of the year, if the plant is left warm, it is good not to water it; during the vegetative period, provide fertilizer for orchids, every 25-30 days, dissolved in the water used for watering.
These orchids develop in a fertile, deep and well-drained soil; use the finely chopped orchid mixture, mixing a high percentage of leaf and peat soil, and a small handful of mature organic fertilizer.
In general the diuris develop large colonies, since the tubers tend to spread under the ground and to continuously produce new plants; if you want to grow these beautiful orchids in pots, remember to use a large container, or to divide the tubers often.
In the case of cultivation in a container, it is therefore advisable to provide a constant repotting during the vegetative rest to avoid causing suffering to the specimens.
The reproduction of these plants, in nature, occurs by seed; it seems that in Australia any forest vegetation fires are of help to the seed germination of these orchids. If desired, it is possible to propagate the Diuris by removing from the tubers portions provided with some well-developed roots: the new plants thus obtained are immediately buried in the ground, using a fertile and well-drained soil.
Diuris: Pests and diseases
Generally these orchids are not attacked by pests or diseases; in the places of origin these plants are becoming extinct due to the fauna introduced by humans in Australia, mice and rabbits feed on the tubers of diuris.