Queen of orchids Cattleya

The Queen of orchids, corsage orchid, or cat orchid is a tropical epiphyte in the Orchidaceae family. It is native to the tropical New World, USDA zones 10 to 12, found from Costa Rica to Argentina. Having been avidly and recklessly collected during the 1800's, Cattleya is now on the CITES Appendix II. All Cattleyas for sale should now be produced in greenhouses. An epiphyte grows in the branches of tall jungle trees where its fleshy rhizomes wrap around the branches for stability. It gets its nutrients from the air, water and decaying plant matter that collect around the rhizomes. All of this makes it a little tricky to grow at home – very special quick draining soil, high humidity, very specialized light requirements, jungle temperatures. However, Cattleya are among the easiest orchids to grow. And it is all worth it when you produce your first spectacular, fragrant flower.

The genus, Cattleya,  takes its name from an avid English 19th century plant collector, William Cattley from Barnet in London.

The plant has three main parts – thick, fleshy rhizomes for support with a fleshy covering that acts as a water retention area, one or two leaves and pseudobulbs. The pseudobulbs, 1-3 inches thick, are food and water storage organs that also bear the flowers on single naked stems. The flowers come in just about every color except true blue and black. When a plant has seven or more pseudobulbs it can be divided. Each new plant must have at least three or four pseudobulbs.

The cultivation of Cattleya as a house plant requires a potting soil of open rooting compost (for example, coarse redwood or fir bark, epiphytic orchid mix) for circulation of air and water and just the correct amount of light. An East or West facing window is best. Direct sun will burn the leaves. A leaf with the right amount of sun is mid-green. A dark leaf indicates insufficient sunlight. The temperatures must be between 70 to 85° F during the day and 55 to 60° F at night. The humidity must be above 50%. This can be achieved by placing a saucer filled with medium sized pebbles under the plant. Keep a small amount of water in the saucer but never allow the pot to sit in water. The rhizomes very quickly succumb to root rot. If that isn't enough to maintain the right level of humidity, mist in the morning so the leaves can dry out before the temperatures drop at night. A mature plant will need water once a week. The plant must dry out completely between waterings. If you aren't sure if it is dried out, leave it two days. Most house plants are killed by overwatering. Water the plant by placing it in a sink and running a not too strong stream of lukewarm water through the pot for a minute or so. Let the pot drain well before returning it to it's place. Do not use salt-softened water or water cooler than 50° F. Do not use ice cubes.

Fertilize regularly after watering with a balanced fertilizer twice a month at half strength or weekly at quarter strength. Repot as needed (usually every two years) in spring or just before new roots sprout from the rhizome. Repotting is needed when the rhizome of the plant protrudes over the edge of the pot or when the potting medium breaks down and drains poorly. To propagate through division, retain three to five of the younger pseudobulbs (stems) and place the cut rhizome against the side of the pot.

Diseases, Insect Pests, and Other Plant Problems:

If kept outside, the plant may be attacked by slugs, snails, thrips, scale insects and mealy bugs. Search the plant periodically for spider mites. They can  be an indication of low humidity.

Quick ID:

• Thin pseudobulbs that emerge from the rhizome
• Thick, waxy leaves
• Colorful flowers with wide segments

VIDEO Created by Laura Barth for "Houseplants, Succulents, and Cacti", a plant identification course offered in partnership with Longwood Gardens.