Cymbidium orchids are a captivating genus of flowering plants renowned for their elegant and long-lasting blooms. These orchids, sometimes called “boat orchids” due to the shape of their lip, offer a remarkable display of beauty. Their appeal stems from their striking floral arrangements and the ability of their flowers to persist for an extended period, often several weeks. Originating from the mountainous regions of Asia and Australia, Cymbidiums have been cultivated for thousands of years.
Cymbidium Orchid Varieties
The Cymbidium genus displays notable diversity, encompassing approximately 50 species and numerous natural hybrids. These orchids are broadly categorized into standard (large-flowered) and miniature varieties. Standard Cymbidiums, with blooms often reaching up to 5 inches wide, are frequently cultivated for cut flower displays due to their impressive size and long stems. These larger varieties require cooler temperatures to initiate flowering.
In contrast, miniature Cymbidiums offer a more compact growth habit, suitable for indoor pots and smaller spaces. Their flowers, while smaller, are equally beautiful and can bloom at slightly warmer temperatures than their standard counterparts. Both standard and miniature varieties come in a wide spectrum of colors, including white, yellow, green, pink, and various patterns. Some species and hybrids are also known for their pleasant fragrance.
Essential Care for Cymbidium Orchids
Light
Cymbidium orchids require bright, indirect light to thrive and produce blooms. An east-facing window is often ideal indoors, or a south-facing window with a sheer curtain to diffuse intense light. If grown outdoors, place them in a location with bright, filtered light, such as under a pine tree or shrub, to avoid direct, scorching sun. Yellow-green foliage indicates proper light exposure; dark green suggests insufficient light, while yellow or reddish leaves signal too much light.
Watering
Consistent moisture is important for Cymbidiums, as they are semi-terrestrial orchids. The potting medium should approach dryness but never become completely dry between waterings. During active growth in spring and summer, water frequently and thoroughly, ensuring water drains completely from the pot to prevent waterlogging. In cooler months or during dormancy, reduce watering frequency. Water with tepid water in the morning to allow the plant to dry before nightfall, which helps prevent fungal issues.
Temperature and Humidity
Cymbidiums prefer a distinct temperature difference between day and night for optimal growth. Ideal daytime temperatures range from 75°F to 85°F (23.9°C to 29.4°C), while nighttime temperatures should fall between 50°F to 60°F (10°C to 15.6°C).
Moderate humidity levels, around 50%, are suitable for Cymbidiums, especially when budding. In dry indoor environments, increase humidity by placing the pot on a pebble tray filled with water, ensuring the pot does not sit directly in the water. Good air circulation is also important, particularly in humid conditions, to prevent fungal issues.
Fertilizing
Cymbidiums benefit from regular fertilization, especially during their active growing season from spring to early fall. A balanced orchid fertilizer, such as a 20-20-20 formulation, is suitable for general maintenance. During the blooming season, switch to a bloom booster fertilizer with a higher phosphorus content, like 10-30-20, to support flower development. Always dilute fertilizers to half or even a quarter of the recommended strength to prevent root damage, and water plants thoroughly before application. During winter dormancy, reduce or stop fertilization.
Potting Mix
The proper potting mix for Cymbidium orchids provides excellent drainage and aeration while retaining some moisture. A common and effective blend includes medium-grade fir or pine bark, perlite, and sphagnum moss. Bark provides structural support and aeration, perlite enhances drainage and keeps the mix airy, and sphagnum moss helps with moisture retention without causing sogginess. Charcoal can also be added to absorb impurities and maintain freshness.
Encouraging Blooms and Post-Bloom Care
Encouraging Cymbidium orchids to re-bloom depends on providing the right environmental cues, particularly a significant temperature drop. A period of cool nights, ideally between 50°F to 60°F (10°C to 15.6°C), is crucial in late summer and fall to initiate flower spike development. Without this temperature differential, especially for standard varieties, plants may produce lush foliage but fail to bloom. Keeping temperatures below 75°F (23.8°C) during fall, winter, and early spring is also advised for blooming. Once flower spikes emerge, stake them carefully to provide support and ensure upright development.
After flowering, typically in late winter or early spring, cut spent flower spikes close to the plant’s base. Cymbidiums do not re-bloom from the same spike. This post-bloom period is an opportune time to transition the plant back into its active growth cycle, focusing on consistent watering and fertilization to build energy for the next season’s blooms.
Repotting Cymbidium Orchids
Cymbidium orchids generally require repotting every two to three years, or when the potting medium decomposes and no longer provides adequate drainage and aeration. Signs include roots growing out of the pot or a decline in plant vigor. The best time to repot is typically in the spring after the plant has finished flowering, allowing it to establish in the new medium during its active growth phase.
When repotting, select a pot that allows for approximately two years of new growth; over-potting can lead to root problems. Gently remove the plant from its old container and carefully remove as much old potting material as possible. Inspect the roots, trimming away any dead, mushy, or damaged roots with sterilized tools. If the plant has outgrown its pot, it can be divided, ensuring each new division has at least three to five pseudobulbs to support new growth. Place the orchid in the new pot, ensuring the base of the pseudobulbs is just at the surface of the fresh, well-draining potting mix, then gently firm the mix around the roots.
Troubleshooting Common Cymbidium Issues
A common challenge for Cymbidium growers is a lack of blooms. This often stems from insufficient light or the absence of cool night temperatures in late summer and fall that trigger flower spike initiation.
Yellowing leaves can indicate several issues. Overwatering, which leads to root rot, is a frequent cause, as roots become mushy and unable to absorb nutrients. Conversely, severe underwatering can also cause leaves to yellow. Nutrient deficiencies, particularly nitrogen, might also result in yellowing foliage. Inspecting roots and checking watering habits helps determine the correct course of action.
Cymbidiums can occasionally encounter pests like spider mites or scale insects. Spider mites often appear as tiny white dots on the undersides of leaves, leading to a silvery appearance, while scale looks like small, brown, umbrella-like structures on leaf surfaces. Fungal issues, such as root rot, are caused by overwatering or poorly draining potting mixes. Improving air circulation and ensuring proper watering practices are key preventative measures. If root rot is present, remove affected roots and repot the plant in fresh, dry medium.