Paphiopedilum (Lady’s-slipper orchid)
Paphiopedilums are semi-terrestrial orchids that are typically found growing on the forest floor in rich humus. The genus is native to Southeast Asia, southern China and the Indian subcontinent. Paphiopedilums are called slipper orchids because of their unique floral pouch. They are fairly easy to grow as houseplants, their care being similar to African violets.
Paphiopedilums are classified as low light orchids. Indirect light conditions are ideal; windows with intense, direct light may be used if shaded by a sheer curtain. If the plant is getting too much light, a reddish tinge will develop on the leaf edges. If the plant does not rebloom, it may not be receiving a sufficient amount of light.
There are two groups of Paphiopedilums which are classified by temperature. Those with mottled leaves prefer warmer temperatures than the cool-growing, green-leaved types. In general, Paphiopedilums prefer 75 to 85 degrees F during the day and 60 to 65 degrees F at night. The cool-growing green-leaved types can be kept colder at night—50 to 60 degrees F. In general, these orchids prefer the same temperatures we do in the home. They can tolerate temperature extremes from 95 degrees F down to the mid 40 degrees F.
These orchids do not have water-storing stems (pseudobulbs), so they require a moist, but not soggy, growth medium. Water a mature plant every five to seven days by placing it in the sink and allowing lukewarm water to run through the pot for a minute or so. Do not use cold water. Drain the plant completely.Do not use salt-softened water.
Paphiopedilums require humidity between 40 and 50%. To increase humidity 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 water or the roots will rot.
Fertilize your Paphiopedilum with a quarter strength balanced orchid fertilizer (20-20-20) once a week after watering. Once a month flush the pot with clear water to remove salt accumulation from the fertilizer. These salts can burn the sensitive, hairy roots. Other formulations may be used depending upon the time of year. Fertilizer applications may be reduced to once a month during winter.
Ideally, repotting should take place annually, as finer grade bark mixes are used for Paphiopedilums. Purchase a commercial orchid potting mix labelled for this genus. Other ingredients such as perlite and horticultural charcoal may be included with the fir or sequoia bark of the orchid potting mix. Moisture retention and good drainage are required. While handling, gently clean the roots and remove any dead roots with a sterile blade or pruners. Always sterilize your tools between plants so as not to spread disease. Use a suitable disinfectant such as bleach. Place a small amount of culture medium on the bottom of a sterile plastic or clay pot that has bottom drainage holes. Place the plant in the center of the pot and spread the roots. Add growth medium around the roots so that the junction of roots and stem is buried one half inch. It is very important to not overpot; Paphiopedilums like ‘tight shoes’. Label the plant and include the repotting date on the label to keep track of when it needs to repotted again.
Paphiopedilums will typically produce one flower per spike, but some species may produce multiple flowers on a single stem. Therefore, it is best to wait until the spike turns brown before cutting it off. One can expect blooms to appear typically between autumn and spring, and last approximately 6 to 8 weeks.