Southern California Garden Club's

2004 - 2005 Signature Plant - Orchid

Learn about the fascinating orchid -
excerpts taken from The Green Thumb,
Southern California Garden Club's award-winning newsletter.

Before you buy an orchid, think about where you plan to keep it as different species do best at specific light and temperature ranges. Match the plant to the place to get the best bloom.

Some of the best windowsill orchids and their preferred conditions include:

• Paphiopedilums: These exotic relatives of the familiar lady-slipper need low to medium light (an east or west-facing window) and prefer temperatures between 55° and 75°F.
• Phalaenopsis: The “moth orchid” needs low to medium light and temperatures between 70° and 80°F.
• Cattleyas: The classic corsage orchid needs medium to high light conditions (a south facing window) and temperatures of 70°-80°F.
• Equitant oncidiums: The “butterfly orchid” needs the same conditions as cattleyas.

When buying orchids, consider two other points. First, although orchids bloom for a long time (sometimes months), when not in bloom they are foliage plants. Some paphiopedilums and phaloenopsis have beautifully patterned leaves. Second, orchids can take years to reach blooming size, so when you buy a plant ask for one that is “blooming size” and you will be enjoying flowers the first year.

Rodale's All-New Encyclopedia of Organic Gardening

ORCHIDS – Terrestrial Orchids

Orchids that grow on the ground such as the European species and those that grow in open grassland in the tropics are the terrestrial orchids. They usually grow with their bulbs or creeping rhizomes and roots below the ground level. Only their leaves and flower spike appear above ground during the appropriate season.

ORCHIDS – Epiphytic Orchids

The tropical rainforests that stretch across the major continents are home to the greatest diversity of orchids and the most beautiful flowers we cultivate today. The majority of orchids in these jungles are epiphytes, growing in the branches of trees. They are not parasites that draw nourishment from their hosts, but simply use them for support and to remove themselves from the competition of other plants on the forest floor.

Large, heavy plants occupy the lower parts or major limbs of the trees and the smaller, lighter plants occupy the twiggy top branches. There are many species found in between.

Some orchids grow on deciduous trees that lose their leaves during the dry season. This exposes the plants to many months of bright sun. Others are much more at home in the evergreen forests living in permanent twilight.

Epiphytic orchids have two growth patters: monopodial and sympodial.

Monopodial orchids have a leafy stem that grows continuously from the top. These plants are not necessarily tall, in many the growth is restricted and they keep their compact shape. The flowers develop along the stems, typically in the leaf joints. Roots may grow along the stem as well as the base of the plant. After the resting season is over, growth will resume at the top of the stem. Monopodial orchids include vandas, phalenopsis, and angraeve.

Sympodial orchids have a creeping rhizome (a horizontal stem growing at or below ground level). Now shoots grow from it each year. The flower spike often appears at the end of the stem, although it may originate from the base of the plant. Most of these orchids produce pseudobulbs (like tubers) which vary greatly in size, shape and arrangement. Pseudobulbs help the plants cope with wet and dry seasons. The plants make a new pseudobulb during the rainy season to store the moisture for the plant to survive during the long periods of drought.

During the rainy season the plant has to develop as much new growth as possible. Some species are completely deciduous, losing their leaves altogether during the dry season. Others live in evergreen forests where there is little or no dry period. They can grow continuously and flower all year round. Some epiphytes have no pseudobulbs at all just thick fleshy tufts. These leaves can sustain moisture and nourishment just as the pseudobulbs do.

Brian and Sara Rittershausen – Orchids

ORCHIDS – Cattleya (KAT-lee-ah)

Cattleyas are the classic orchid, a beautiful flower known for its purple blooms. Along with these classic types, there are many other variations in form and color.

This wonderful genus is spread throughout the Americas, form Mexico though out Central America all the way to the Pampus.

Cattleyas are among the most commonly grown orchids and there culture is often used as the basis for comparison with other types of orchids. Like many orchids, Cattleyas are epiphytes, or air plants. They have well-developed water storage organs (pseudobulbs) and large, fleshy roots. Pot in porous, free-draining medium such as fir bark, shredded tree-fern fiber or various types of rock. Keep them out of the cold when they are in bloom.

LIGHT - Provide bright light, some sun, as in an east, west, or lightly shaded south window. Plants should be naturally erect without staking and of a medium olive-green color. If your Cattleya is limp and dark green, it is receiving too much light.

TEMPERATURE - Mature plants need 15-20°F difference between day and night temperatures. Nights of 55°-60°F and days 70°-85°F are preferred. They can tolerate temperatures up to 95°-100°F if shading, humidity and air circulation are increased.

WATER - Mature plants prefer to dry out between watering. Seedlings need more constant moisture.

HUMIDITY - Place on trays over moistened pebbles to achieve 50-60% humidity.

FERTILIZER - Fertilize weakly weekly. Regular feeding promotes good growth. Use a balanced fertilizer or one higher in nitrogen such as 10-5-5. Micro-nutrients are always desirable with the inert orchid mixes.

POTTING - Should be done every two to three years in spring before the potting mix breaks down. Pot firmly in media that has good aeration and good drainage allowing enough room for two years growth.

American Orchid Society

ORCHIDS – Cymbidiun (sym-BID-ee-um)

Cymbidiums are among the most popular of spring flowering orchids and are often grown as garden plants. Their striking sprays of long-lasting blooms provide ideal home or patio choices and are often used as cut flowers.

There are standard (large-flowered) and miniature (smaller-flowered) types. The miniatures are more heat tolerant. Cymbidiums are not successful as houseplants. They are terrestrial plants and require a moisture-retentive but well-drained mix. Fir bark is most commonly used.

LIGHT - Cymbidiums prefer very bright light up to 80% of full sun. Leaves should be naturally erect and of a medium olive green color. Dark green, limp foliage indicates too much light.

TEMPERATURE - Night of 55°-60°F though temperatures in the 30s are tolerated. Day temperatures of 70°-80°F are preferred, but temperatures up to 95°-100°F can be tolerated if shading, humidity and air circulation are increased.

WATER - Mature plants must never dry out between watering.

HUMIDITY - Cymbidiums need 50-60%.

FERTILIZER - Fertilize on a regular basis- “weakly weekly” using ¼ to ½ the recommended amount of a balanced fertilizer every week.

POTTING - Repot every two to three years in spring immediately after flowering to allow maximum time to re-establish before the next flowering season.

ORCHIDS – Phalaenopsis (fayl-eh-NOP-sis)

This has become America’s favorite orchid. Suited to growing in the home, they have long-lasting sprays of lovely moth-like blooms in a broad array of colors. The main flowering season is late winter into spring though commercial growers can make flowering Phalaenopsis available year round.

LIGHT - They like bright filtered or indirect light. No direct sun. In the home, an east, west or shaded south window is good.

TEMPERATURE - Mature plants need a 15-20°F difference between day and night temperatures. Nights of 60-65° and days of 75-85° are preferred. Seedlings need temperatures 5-10° higher than mature plants.

WATER - Mature plants should seldom dry out between watering. Seedlings especially need constant attention to moisture.

HUMIDITY - Place on trays over moistened pebbles to achieve 50-60% humidity.

FERTILIZER - Fertilize on a regular basis-“weakly weekly” using ¼ to ½ the recommended amount of a balanced fertilizer every week.

POTTING - This should be done every one to two years before the mix breaks down too far. It is best done in late spring after main flowering season using a well drained but water-retentive mix. Select the pot size for root mass not top size.

American Orchid Society

ORCHIDS – Paphiopedilum (paff-ee-oh-PED-ih-lum)

The Slipper Orchid

Paphiopedilums are the Old World orchid relatives of North America”s temperate-zone lady’s slipper orchids, the cypripediums. Perhaps no other orchid the same dedication as these semi-terrestrials. “Paphs” are one of the best orchids for home growing, requiring only fairly bright light and normal home temperatures. They provide some of the orchid kingdom’s longest-lasting and most exotic blooms. There are several general types of paphs each requiring slightly different care. Slipper orchid blooms can last eight to ten weeks or more.

LIGHT - Bright light, but no direct sun. They prefer an east, west or shaded south window. Foliage should be naturally semi-erect and firm, not drooping. Dark green, limp foliage indicates too little light.

TEMPERATURE - Mature plants need 15-20°F difference between day and night temperatures.

Nights of 55-60°F, days of 70-85°F. Seedlings need temperatures 5-10° higher than mature plants.

WATER - Mature plants should never dry out between watering. Seedlings need constant attention to moisture.

HUMIDITY - Paphiopedilums need 60-70%. Achieve this in the home by placing the plants on trays of moistened pebbles.

FERTILIZER - Must be provided on a regular basis although paphiopedilums will grow and flower with less fertilizer than will most orchids.

POTTING - Repot every two to three years. Any time of year is all right. Use well drained, but water retentive mix.

American Orchid Society

Where DO I Cut the Flower Spike when it is Finished?

When most orchids have finished blooming, the spike should be cut off with s sharp, sterile blade close to the base of the spike. Of all the more commonly available orchids, on phalaenopsis (the moth orchid) will re-bloom from an old spike. Phalaenopsis will usually re-bloom given a little extra care. Cut between the scar left by the first flower and the last node (swollen jointed area on the stem). One of the lower nodes will initiate a new spike that will generally produce flowers within eight to twelve weeks. Younger or weaker plants may not re-bloom. It is also a good idea to cut the spike off entirely by midsummer to allow the plant to grow strongly to produce next year’s bloom.

How Often Should I Water?

Water once every four to seven days depending on the season and dryness. Allow the plants to approach dryness. You can gauge this by the weight of the pot or by the pencil trick. The point of a sharpened lead pencil when inserted into the medium will darken if moisture is present. Apply sufficient water (room temperature) so it drains freely through the container. Never allow any potted plant to sit in water.

When plants are flowering, they may require more frequent watering to make up for the greater burden of the flowers. Plants require less water when not actively growing (generally winter months) and more while growing (usually spring and summer months). Increasing the frequency of watering will not make up for a poor root system.