Coryanthes macrantha (Monkey orchid)
Coryanthes macrantha buds
Coryanthes, commonly known as Bucket Orchids, is a genus of tropical epiphytic orchids. This genus is abbreviated as Crths in horticultural trade. The distribution of the genus Coryanthes extends from Mexico in the North to Bolivia and Brazil in the South. The plants prefer habitats with high humidity and high temperatures, they were often encountered near rivers in primary forest. They grow in altitudes from sea level up to 1200 m.
Bucket orchids are an excellent example of coevolution and mutualism, as the orchids have evolved along with orchid bees (the tribe Euglossini of the family Apidae) and both depend on each other for reproduction. One to three flowers are borne on a pendant stem that comes from the base of the pseudobulbs. The flower secretes a fluid into the flower lip, which is shaped like a bucket. The male orchid bees (not the females) are attracted to the flower by a strong scent from aromatic oils, which they store in specialized spongy pouches inside their swollen hind legs, as they appear to use the scent in their courtship dances in order to attract females. The bees, trying to get the waxy substance containing the scent, sometimes fall to the fluid-filled bucket. As they are trying to escape, they find that there are some small knobs on which they can climb on, while the rest of the lip is lined with smooth, downward-pointing hairs, upon which their claws cannot find a grip. The knobs lead to a spout, but as the bee is trying to escape, the spout constricts. At that same moment, the small packets containing the pollen of the orchid get pressed against the thorax of the bee. However, the glue on the pollen packets does not set immediately, so the orchid keeps the bee trapped until the glue has set. Once the glue has set, the bee is let free and he can now dry his wings and fly off. His ordeal may have taken as long as forty-five minutes. Hopefully, the bee will go to another flower, where, if the flower is to be successful at reproducing, the bee falls once again into the bucket of the same species. This time the pollen packets get stuck to the stigma as the bee is escaping, and after a while the orchid will produce a seed pod.
The bee, having stored the aromatic oils in his back legs, can then fly off to mate with a female bee.
The name Coryanthes finds its origin out of Greek and is composed out of two words corys (helmet) en anthos (flower), which refers to the lip of the flower which looks like a helmet. The name bucket orchid is also a common word for this flower and is also referring to the shape of the flowers.
Coryanthes has the heaviest flowers in orchidaceae, the biggest one C. bruchmuelleri have a weight of more than 100g.
The flowers occur underneath the bulb and the inflorences are mostly going right down vertically in the soil. So the best way to grow Coryanthes is in a wooden basket or in pots with big holes big enough to let the inflorences come out. On one inflorence occurs 1 to 4 flowers.
when you succeed to create the natural conditions like the way Coryanthes grows in its natural habitat, you won’t find much trouble.
Temperature: Warm to hot.
Light: Bright, but no direct sun.
Water-Humidity: Evenly moist, 70 to 80% humidity.
Fertilizer: During the growing season they are strong feeders, application of Osmocote is quite helpful (don’t work the granules into the compost).
Potting: Medium grade bark, basket culture, repotting should be done before compost breaks down, Coryanthes are very sensitive against “sour” compost.
They don’t like to dry out; water these orchids often. As for Stanhopeas, I recommend a moisture-retentive, but breathable, potting mix involving one or more of sphagnum moss, fine fir bark, rockwool, coconut fiber, or osmunda.
They do well with bright, indirect light, about 3000 footcandles: basically, use Cattleya lighting. Intermediate-to-warm temperatures are best; 70-80°F (21-27C) during the day, dropping by 10 15°F (6-8C) at night.
50-70% humidity will keep them happy.
The culture of Coryanthes needs some experience and this type of orchids is not directly appropriate to start your hobby when you have no experience with orchids or tropical plants. On the other hand, when you succeed to create the natural conditions like the way Coryanthes grows in its natural habitat, you won’t find much trouble.
A high humidity is an important factor, I ‘ll advise you to keep it up to 70-80%, because it will keep away insects like spider mites (they dislike a moist atmosphere). But the main reason for a humid atmosphere is to create an imitation of the natural circumstances.
This orchid likes to be watered frequently and when the plant is actively growing the soil may not dry out completely. In rest the plant may be kept a little dryer. During spring and summer the plant needs fertilizer with a high nitrogen value to encourage growth. During summer and autumn you can use fertilizer with a high phosphor value to stimulate the production of flowers. Phosphor even helps for the development of the root system. Be careful with fertilizing during winter, the plants doesn’t need much at this time of the year.
Besides attention for fertility and humidity of the soil there is one other thing you need to consider namely the acidity of the soil. In their natural habitat Coryanthes grows in ant nests, and these ants are producing an acid. While you are actively keeping up de pH value of your other orchids, and you are taking care that the soil not drops to citrus-value, you need to take care that the soil of Coryanthes is acid! The pH value of Coryanthes may even drop to 3. There are several ways to accomplish a low pH value, but I usually use juice of lemon, which I apply to water. This water with juice will give a little acid. Despite of the fact that acid can prosper growth and is part of the natural habitat, it is not the most important thing for a healthy growth. The ants do not only take care for sour soil, but more important they are the gardeners of the garden of Coryanthes. They take care of a proper amount of moist- and fertilizer and even defend the area around and on the Coryanthes. All other animals not being the same ant as living with Coryanthes is being eliminated directly.
Coryanthes leaves are very vulnerable for spider mites or greenfly. To avoid infection with these animals, study regularly the plant and especially the leaves. When you spot nasty insects a quick response is important.