This unusual group of orchids offers fascinating, waxy flowers that often have the peculiar habit of discharging their pollen masses (pollinia) onto pollinators. Almost always deciduous, the pseudobulbous plants have strict growing and resting periods. Most flower before entering a dormant period when they drop their leaves. This group also has separate, usually green helmet-shaped female flowers (which is identical across species), and the showy, unique male flowers, usually with heavy, pleasant fragrances, ranging from wintergreen to sweet like ice cream. This group includes Clowesia, Catasetum, Mormodes, Fredclarkeara, and more.
DECIDUOUS Catasetum-type plants hail from tropical seasonal climates – there is typically a wet, hot summer followed by a cooler (usually room temperature), dry winter. To minimize water loss during the winter, these plants will drop their leaves. New growths with leaves will come about in the spring, with increasing light. As soon as you see a new growth, do not let them dry out much until it’s time for them to go into dormancy. Some species/hybrids will tell you when they are going dormant; others will need to be pushed into dormancy with the reduction of water and temperature at the end of the growing season.
LIGHT
Should be strong. Plants grow best with light levels of 32,000-65,000 lumens/3,000 to 6,000 foot-candles. If using artificial lights, they should be on for 12 to 16 hours a day.
- In the greenhouse, 70% to 80% shade will provide sufficient light levels.
- In the home, they should be in a window that gets >4hours of direct sun a day.
More light should be provided during dormancy, as in nature, the plants become more exposed to direct sun.
TEMPERATURES
Affect this group of orchids moreso than others. Like many tropical plants, Catasetum-type plants will grow faster with more heat. Do not let Catasetum-type plants get cooler than 65F (18.3C), or you may arrest their growth and trigger dormancy.
During the growing period, day temperatures of 80F to 100F/26.6C-37.7C and night temperatures of 65F-75F (18.3C-23.8C) are beneficial. After growths mature, temperatures can be reduced to day temperatures of 70F to 85F.
WATER
When thinking about these plants’ water needs, think about the environments that they come from – mostly seasonally wet savannah. That means that there’s a distinct wet and dry season that you have to emulate for the plant. During active growth (regardless of growing indoors or in a greenhouse), water should be liberally applied. Potting mix should be moist and dry slightly between watering. Plants should not dry out completely during growth. If growing indoors, you may keep the plant sitting in a tray of water that’s about ½” deep. If adding more water, always add to the top of the media. Avoid wetting foliage or allowing water to sit in the center of the growth.
As plants enter dormancy in fall, allow the potting mix to start drying out more over time.
- In a greenhouse – during dormancy, water should be nearly completely withheld.
- Indoors – during dormancy, keep the media lightly moist like a wrung-out sponge. This can be done by an occasional light watering or spritzing the media. Media can completely dry out, but not for more than a few days.
During dormancy, if needed, water lightly to rehydrate the pseudobulbs if shriveled severely.
HUMIDITY
for either a greenhouse or indoors should be higher during dormancy, >60% unless you are lightly spritzing each day. In a greenhouse, air should always be moving around the plants to prevent fungal or bacterial disease, especially if high humidity or cool temperatures exist.
FERTILIZER
Fertilize and water regularly to produce strong pseudobulbs. Use regular strength to ½ strength of a high nitrogen formulation (such as 30-10-10) while plants are in active growth, slowly tapering off as pseudobulbs forms. A blossom-booster formulation (such as 10-30-20) should be used as flower spikes are forming. Do not fertilize during dormancy.
POTTING
Potting should be timed to coincide with the initiation of new growth, usually in the spring. New roots will be produced quickly at that time, and plants will experience minimal setback. These plants have vigorous root systems and require a rich, moist potting medium during the growing season. Many greenhouse growers bare-root their plants during the resting period to ensure dryness at that time. Indoor growers do not need to bare root for dormancy, as room temperatures are cool enough, and the spritzing/very light waterings are ok. Fine-grade orchid bark mix and sphagnum media are common for smaller pots; medium-grade media are used only in larger pots. Sphagnum moss is used successfully for plants in many areas, as it provides tremendous water and fertilizer-holding capacities. Some plants can be grown on slabs of tree fern or other material, which makes it easier to keep them dry during dormancy; however, it is harder to keep them moist while growing. When well-grown, these orchids can be divided down to one mature pseudobulb and will then flower on the next mature growth.
OTHER
Spider mites are a common pest of these orchids when in leaf. Control spider mites by keeping humidity high or spraying with recommended miticides.