hese orchids are prized for their long-lasting sprays of flowers, used especially as cut flowers or for corsages. There are two main types of cymbidiums; standards and miniatures. Standard cymbidiums have strap shaped leaves 3 to 4 feet long. Miniature Cymbidiums have leaves about half that size. Flower stalks will grow to about three-quarters the length of the leaves. Because the leaves are soft and flexible, they fold over at mid length exposing the flower stalks above the strap shaped leaves.

Cymbidium orchids have a sympodial growth form. They produce pseudo-bulbs which are swollen basal stems which store food and water, enabling them to survive dry seasons. They produce at least one per year and are joined by an underground stem (rhizome). The pseudo-bulbs produce strap-like leaves which live for two to four years. When the leaves die and are shed, the bare pseudo-bulb lives two to three more years and is called a back bulb.

In nature, Cymbidiums are semi-terrestrial plants called hemiepiphytes. They grow on the ground surface with their roots embedding themselves in the soft, fluffy humus of the forest floor. In the Bay Area, Cymbidiums are most happy in containers. Wood, plastic, terra cotta or the new lightweight Eurocast containers all work equally well. Many people have their own “secret” container mixes but we find that a potting mix of one-half E.B. Stone Orchid Mix and one-half orchid bark (1 inch in diameter) to which about one-eighth part perlite has been added works very well. Then, top dress with straight orchid bark for a neat appearance.

Outside conditions on the Peninsula are almost perfect for Cymbidium culture. The potted plants should be placed outdoors under a light foliaged tree such as a birch or on a porch or patio where they will receive morning or afternoon sun. Full sun from 11 a.m. to 3 p.m. is too hot. The Cymbidium leaves should be slightly yellow. If they are a deep, dark green, they are not getting enough sun. If they are mostly yellow with some brown spots, they have been sunburned by too much sun.

Cymbidiums also need fall chilling in order to bloom well; the standards more so than the miniatures. They should be located where the night time temperature will drop below 55°F during October/November. If the plants are located on a concrete porch or patio be aware that the concrete may hold daytime heat during the night and prevent the fall chilling. Set the pots on strips of wood lath to avoid this heat transfer. Don’t worry about winter freezing unless the temperature drops below 25°F.

Water Cymbidiums once or twice a week during the late spring and summer, when most of their vegetative growth takes place. Leave no standing water in the pot saucer lest the bark starts to rot. The bark and mix down about 2 inches should be moist but not soggy. Cut back on water in late summer and keep the mix barely moist during the winter.

The potting mix used for Cymbidiums has little nutrient value so it is necessary to fertilize the plants on a regular basis. Orchidists recommend a high Nitrogen fertilizer (30-10-10±) from spring through late summer. After that, switch to a high Phosphorus blossom-booster fertilizer (±10-30-20). Fertilize with these mixtures every two weeks. An alternative is to use time release Osmocote (14-14-14) once every four months. If Osmocote is used, give a supplemental feeding with fish emulsion fertilizer in February to provide for any missing micronutrients.

It’s time to repot your Cymbidiums when the roots come out the drain hole or they fill the pot so the bulbs are bumping against the edge of the pot or the roots are lifting the plant up out of the pot. Repotting should occur as soon as possible after the orchid has bloomed. These events will occur every two to five years depending on the size of the pot. 

Knock the plant out of the pot and use a saw to cut off one-half to two-thirds of the root mass. Discard the severed roots. Separate the balance of the orchid cluster into two or three bulb segments. If a back bulb becomes part of the segment, that’s fine. Repot into a two gallon or larger container. Lay about two inches of orchid bark in the bottom of the container and then fill to within four to six inches from the top with Orchid Mix. Hold a cluster of leaves and bulbs and place them in the center of the container so there is an inch or two of clearance to the edge of the pot. Fill with Orchid Mix and ram into position with a once-inch wooden rod. Pushing down the Orchid Mix with the rod will leave an inch or more of space at the top. Add more Orchid Mix if needed and then fill to the top with Orchid Bark to give a more finished appearance. Water your repotted orchid until the water runs out the bottom. Water again, half an hour later to ensure that the bark has been moistened.

The back bulbs from the repotting can be discarded or potted up in one gallon cans. It will take four to eight months for the back bulbs to sprout new leaves and four years for the first flowers to develop.