The genus Calochilus includes about ten species of terricolous orchids, originating from the Australian continent; in spite of the beauty of the flowers in general, these plants, although easily found in nature in the places of origin, cannot easily be found cultivated specimens. From large oval tubers a single elongated basal leaf develops, dark green, thick and fleshy; from the tuber also develops the stem that bears the flowers, erect, 30-50 cm high, from which in spring or late summer 6-14 flowers bloom. The calochilus flowers are quite large, with petals and sepals of yellow or greenish-yellow, often with lines or dots of wine red or brown; the labellum is of considerable size, enlarged, fleshy, dark yellow, purple or brown, and is covered by a thick dark hair, sometimes even blue; in Australia the hair of the labellum has given this orchid the common name of a bearded orchid. At the beginning of the cold months the leaf dries and dies, and the plant goes into vegetative rest until the following spring.
For a good development of these plants, place in a bright place, but protected from direct sunlight, especially during the hottest hours of the day as the leaves could have very dangerous burns; usually the calochilus fear frost, so in winter it is advisable to place the containers with the tubers in a cold greenhouse, or cover them with non-woven fabric and mulch the soil with bark or dry leaves, so as to protect the root system from the harshest temperatures .
From March to October water regularly enough, letting the soil dry slightly between one watering and another, so as to avoid the presence of water stagnations that could quickly lead to dangerous radical rots. In the cold months, avoid watering. During the vegetative period, mix a small amount of fertilizer for orchids with the water, every 25-35 days.
Use balanced universal soil mixed with sand, perlite and a small amount of shredded bark, in order to retain a little moisture. These orchids do not develop quickly, so it is possible to grow them in the same container for a few years, taking care to replace the container when the roots have occupied all the available space. To avoid ruining the root system, rather delicate, it is good to wet the soil before proceeding with the repotting.
Sometimes the tubers tend to multiply: to have a new plant it is sufficient to remove one of the new small tubers and repot it into a single container; these orchids in nature are also propagated by seed, but the sowing in a container does not seem to give many chances of success, in fact the small seedlings obtained from seed generally have a short life, as the repottings are badly tolerated.
Calochilus: Pests and diseases
These orchids are not affected by pests or diseases, even if a soil with poor drainage, or excessive watering, can favor the onset of root rot that must be counteracted quickly to prevent it from leading to the death of the plant.