Stanhopea (J. Frost ex Hook. 1829) is a genus of the orchid family (Orchidaceae) from Central and South America. The abbreviation used in horticultural trade is Stan. The genus was named for the 4th Earl of Stanhope (Philip Henry Stanhope) (1781-1855), president of the Medico-Botanical Society of London (1829-1837).

These epiphytic, but occasionally terrestrial orchids can be found in damp forests from Mexico to NW Argentina. Their ovate pseudobulbs carries one long, plicate, elliptic leaf. It is noted for its complex and usually fragrant flowers that are generally spectacular and short-lived. Their pendant inflorescences are noted for flowering out of the bottom of the containers in which they grow, lending themselves to culture in baskets that have enough open space for the infloresence push through. They are sometimes called aptly upside-down orchids. With most Stanhopea flowers lasting three days or less, the blooms must attract pollinators very quickly. These chemical attractants are generated in the hypochile, attracting the male euglossine bees to the flower. When the bee touches down on the flower, a great effort is made to collect chemical scent - he eventually slides on the waxy surface of the hypochile, gliding down on the slippery lip to exit the flower. The long column is touched in the process, resulting in the bee taking up pollinia at the very tip of the column. When the bee slides down another flower, the pollinia are deposited on the sticky surface of the stigma.

The majority of species are robust plants that grow readily in cultivation.

Stanhopeas are epiphytes that bear the most dramatic looking incredible flowers with intricate and complex structures and mechanisms for pollination, from channeled "walkways" for insects, to buckets of a watery solution. All have inflorescences that grow downward, so the Stanhopeas must be potted in hanging baskets with 1~2" slats spacings at bottom or similar containers. Most flowers are spicily fragrant, and although the flowers are short-lived, each plant may produce many inflorescences throughout the year. Stanhopeas are endemic to the New World ( Central and South America and the Carribeans) Those found in Mexico requires some dry spell in order to flower. Just like the Cymbidiums, when buying Stanhopeas, look for 3 or more pseudobulbs. The more pseudobulbs, the greater the likelihood of flowering in a short time. The usual Stanhopeas seen in the wild have few pseudobulbs.

LIGHT

should be bright, with direct sunlight diffused so as not to burn the leaves. The Stanhopeas need to be suspended due to their pendulous inflorescences. Light levels approximating those for cattleyas, or 3,000 foot-candles, are best.

TEMPERATURES

for Stanhopeas should be moderate: 52 to 60 degrees F at night, with day temperatures 68 to 75 degrees F in the winter. Stanhopeas can stand short spells of higher temperatures, but air movement, humidity and shading must all be increased. Cool night temperatures seem to promote flowering. Many species flower in the summer, and putting them outside in the summer may be ideal.

WATER

in ample quantities is important to produce strong pseudobulbs and healthy flowers. They grow in moist locations in open medium and watered frequently, especially when warm. Dry roots lead to leaf-tip dieback, or a browning of the leaf tip. Watering frequency can be reduced in the winter months, but these Stanhopeas should never dry out completely.

HUMIDITY

should be kept at 50% to 80%, and at high levels especially when temperatures are high. Frequent misting reduces the chance of mite and insect infection; at the same time, strong air movement must be provided to prevent fungal spotting of the foliage.

FERTILIZER

should be applied at regular intervals. Most growers fertilize with a diluted concentration every week to two weeks. The fertilizer formula should match the potting medium. Use 20-20-20 with tree fern, charcoal, or various inorganic aggregates,. We recommend non-urea based fertilizers at half strength. Non urea fertilizers provide 100% immediately available nitrogen, which urea based fertilizers do not. We recommend Grow Mor fertilizers , which also have micro nutrients. The micro nutrients provide strength for the new growth and support for the flowers. For Stanhopeas in bark, but use 30-10-10 with fir bark. During the blooming season, which is mainly summer, use a 6-30-30 bloom booster formulation.

POTTING

is best right after summer bloom, as most Stanhopeas seem to grow year-round. Stanhopeas that rest in the winter may be repotted in the spring. The best flowerings come from large clumps of Stanhopeas, so large baskets with 1~2" spacing between slats are usually used. An airy, yet moist medium seems to work best, such as medium-grade fir bark (often mixed with sphagnum peat) or osmunda fiber. Baskets are most often lined with moss before Stanhopeas are placed in the medium; this allows the pendulous inflorescences to grow through the bottom of the basket. Pre-moisten the potting medium so that the roots do not dry severely after repotting. Vigorous Stanhopeas may need repotting every three years.

TIPS

When you purchase a new Stanhopeas, always place it where you can watch it for a couple of weeks until it is acclimated to your area. Initially, water the plant thoroughly and place it in a bright location with good humidity.

A preventative spraying of Orthene 75%, wettable powder or in aerosol, on maturing flower buds will prevent thirp damage, as well as aphids and ants. If insects are found on the open flowers, the same chemical can be used to eradicate the infestation, without damaging the flowers. Other insecticides WILL damage the flowers and should not be used. Use Orthene spray as recommended on the label. If using the aerosol, spray from at least a foot away from the flowers. In addition, Orthene 75% does not leave any unsightly residue.

Examine your Stanhopeas on a regular basis. Always remove the dried sheathing from pseudobulbs to prevent buildup of moisture, and as a hiding place for insects. In nature, the breeze removes the sheath. In captivity, you must remove the sheath. The removal of the sheath also provides more surface for photosynthesis activity. Insects, particularly scale insects, find Stanhopeas plants attractive. Also slugs and snails will dine on Stanhopeas. Following the label recommendations on your favorite insecticide will usually solve any insect problem. 70% isopropyl alcohol and dish soap make a good alternative insecticide for small outbreaks.