Cattleya (Corsage Orchid)
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The Cattleya orchid is known as the corsage orchid, due to its popularity for use in corsages and wedding arrangements. Native from Costa Rica to Argentina, Cattleyas have beautiful fragrant flowers that come in many colors and combinations of colors. The flowers can range in size from very large to very small and last several weeks to a month. This orchid is an epiphyte, which grows on the branches and trunks of trees, but it does not parasitize them.
Light
Cattleyas are classified as high light orchids. If they do not receive adequate light, they will not bloom. Indirect light is ideal, typical of an unobstructed east or west window. Bright light with some sun is good, but there should be no direct sun in the middle of the day. Sunburn can occur rapidly in direct midday sun. Direct light may be used if shaded by a sheer curtain. If the light is correct, leaves will be a medium green. Dark green leaves indicate the plant is not receiving enough light.
Temperature
Cattleyas are categorized as warm-growing orchids. Temperatures should be 70 to 85 degrees F during the day and 55 to 60 degrees F at night. A 10-15 degree temperature difference between day and night is recommended. These plants will tolerate day temperatures up to 95 degrees F if humidity is high and air circulation is good.
Watering
Mature Cattleyas should be watered thoroughly about once a week or more with lukewarm water. Never use cold water. Seedlings require more frequent watering. It is very important that the plant dry out between waterings, as a constant wet root environment causes root rot. Water by placing the plant in the sink and allow a stream of water to run through the pot for a minute or so. Allow the water to drain thoroughly. Do not use salt-softened water. Water your plants in the morning so the foliage will be dry by nightfall. Wet leaves can encourage disease issues.
Humidity
Humidity should be above 50%, and air should always be moving around the plants. This discourages fungal and bacterial diseases. If humidity in the home is below this threshold, you can place your plant in a shallow tray of pebbles with water on the bottom. Be sure that the bottom of the pot is not in the water or the roots will rot.
Fertilizing
Feed your plant with a balanced orchid fertilizer (20-20-20) at quarter- strength once a week after watering. Other formulations may be used, depending upon the time of year. Once a month flush the pot well with clear water to avoid buildup of fertilizer salts. When plants are actively growing, the fertilizer concentration may be increased to half-strength the label recommendation.
Repotting
Cattleya orchids are sympodial orchids that grow horizontally, with the new rhizome appearing at the base of an older stem (pseudobulb). They should be repotted about every two years when the potting medium is decomposed, and/or the rhizome of the plant protrudes over the edge of the pot. The potting medium at the top of the pot may appear good, but that in the bottom may be completely broken down, so it is important to determine the condition of the culture medium. Repot before new roots sprout from the rhizome, after flowering or in spring. These orchids do not respond well to repotting at the wrong time of year. Purchase a commercial orchid potting medium labelled for Cattleya orchids. This usually consists of a medium- to- coarse fir or sequoia bark, and may be mixed with horticultural charcoal and perlite.
If you choose to divide the plant, assure that each division has at least three and preferably five pseudobulbs, and the roots are healthy. Choose a plastic or clay pot with bottom drainage holes that will allow for two years’ growth. Do not use a pot that is excessively large. Clean the roots and cut off any that are dead. Use a sterile razor blade or sterile pruner to remove them. Always sterilize your tools between plants so as not to spread disease. Use a suitable disinfectant such as bleach. Add a thin layer of orchid potting medium to the bottom of the pot. Place the plant in the pot with the oldest stems against one edge of the pot, allowing new growth to grow horizontally across the pot. Fill the pot with potting medium, working it in with your fingers firmly around the roots. Stake and tie the plant with twine if necessary. Label the plant and record the repotting date on the label to keep track of when it needs to repotted again.
Blooming
With proper care, Cattleyas will flower on average once a year for about 3 to 6 weeks. When the plant is finished blooming, remove the spent flowers. Each pseudobulb blooms only once and flowering occurs on new pseudobulbs.