Vivi's Orchid Corner

May 2002 - Volume 7, Issue 4

"Catasetum tenebrosum"

Dear Orchid Friends:

Catasetum tenebrosum: this unusual species is from Peru. These are deciduous orchids which mean they will drop their leaves. After flowering, they enter a dormant period. This plant requires a dormant period and will drop its leaves completely. This is normal and required by the orchid. Catasetum tenebrosum requires a strict growing and resting period. The genus Catasetum are known for their characteristic trait of depositing pollen onto a pollinator (i.e. bee) which then transports the pollinia onto other Catasetum flowers for pollination, or “shoots” pollen to pollinate, dependent upon the species. Catasetum tenebrosum tolerates variety of planting mediums or may be mounted.

LIGHT: Strong light is necessary, especially when growing and forming flower spikes (spring through autumn). Light is the key to producing flowers. They can handle ¼ to ¾ full sun.

TEMPERATURE: Catasetum tenebrosum can tolerate hot summer days and like cooler weather while dormant. They easily tolerate days of 85F to 100F during the summer. These orchids like hot, tropical environments and do well in summer rainy months. After pseudobulbs mature, they tolerate lower day temperatures at 70-85F and do well at 55-60F at night. This is quite a wide temperature fluctuation. Maintain humidity when in active growth and leaves are on the plant.

WATER: The watering cycle requires a severe change from its growing season to its dormancy period. Water is critical for producing large pseudobulbs and strong flowerings. Water heavily as leaves are forming especially during the spring and summer and when flower spikes are forming. The reason for this is that the plant must store water in its pseudobulbs to sustain the plant through the growing period as well as through dormancy. During hot summers, mist leaves to prevent shriveling during its period of growth. When leaves start to yellow and the plant stops flowering, gradually reduce watering. When the leaves fall off, drastically reduce watering and KEEP ON THE DRY SIDE. The plant is now entering its dormant season and must be kept dry. Water just enough to keep the pseudobulbs from withering. Do not overwater during this dormant period. It is difficult to refrain from watering Catasetum tenebrosum, but this is absolutely critical. REMEMBER, THE ORCHID REQUIRES A STRICT, DRY RESTING PERIOD. So, my best advice is don’t water! The pseudobulbs have deep folds and will appear dry and gray after dropping its leaves.

FERTILIZER: Fertilizer is important to produce strong pseudobulbs. It is important to provide fertilizer on a regular basis. During active growth in the summer, fertilize weekly. Give a bloom booster on occasion during the summer. Taper off the fertilizer as you begin to reduce its watering schedules also. Watch for spider mites when in leaf. Control by keeping humidity high and spray as necessary with miticide products.

FLOWERS: Flowers are velvety black petals with greenish to creamy brown lip. These are distinctive flowers! Flowers are heavy, waxy and quite unique. It flowers in the Peruvian spring which is our autumn. Catasetum tenebrosum flowers prior to entering its dormant period.

Vivi