Orchis Chusua: A Guide to Its Growth and Habitat

Orchis chusua grows between 5-45 cm in height. The tuber is oblong or spherical, fleshy, and undivided. The stem is erect and cylindrical. The leaves are lanceolate, linear-lanceolate, or linear, with no purple spots on the surface.

The inflorescence has 1-20 flowers, mostly leaning to one side; the flowers are purple-red or pink. The petals stand erect, are narrowly ovate, ovate, or oblong-ovate, measuring 5-7 mm in length and 3-4 mm in width with a blunt tip.

The edges of the petals are smooth and without cilia. The lip of the flower protrudes forward, longer and wider than the sepals, with smooth edges and is three-parted. The flowering period is from June to August.

It is found on mountain slopes, under shrubs, alpine shrub grasslands, or alpine meadows at altitudes ranging from 500-4500 meters.

This species is distributed in China, the Korean Peninsula, Japan, Siberia in Russia, Nepal, Sikkim, Bhutan, northern India, and northern Myanmar. The flower is cultivated and holds significant horticultural value.

Morphological Features

Orchis chusua grows between 5-45 cm in height. The tuber is oblong or spherical, 1-1.5 cm in length, and about 1 cm in diameter. The stem is erect, cylindrical, slender or robust, with 1-3 tubular sheaths at the base.

Above the sheath, there are 1-5 leaves, typically 2-3, and sometimes 1-3 smaller, lanceolate bract-like leaves. The leaves are lanceolate to linear, 3-15 cm long, and 0.2-3 cm wide, with no purple spots on the surface. The flowering period is from June to August.

Habitat

Orchis chusua is found on mountain slopes, under shrubs, alpine shrub grasslands, or alpine meadows at altitudes ranging from 500-4500 meters. It’s native to China.

Growth Habits

Orchids typically grow on the sides of secluded mountain valleys, on sloping hillsides or rock crevices with good water permeability and retention, beside sparse mountain grass, and under secondary mixed forests. They prefer shaded places with short sun exposure or scattered light.

Orchids thrive in areas with high humidity and good air circulation, sometimes also on cliffs beside mountain streams.

Orchids should be planted in a well-ventilated environment. They prefer shade and avoid direct sunlight. They thrive in humid conditions, not in dry ones, and grow best between 15℃ to 30℃. Growth is hampered at temperatures above 35℃.

Reproduction Methods

Reproduction can be done in both spring and autumn, typically every three years. Healthy plants with dense pseudobulbs are suitable for division.

After division, at least 5 connected pseudobulbs should be retained in each clump. Before division, water should be reduced to keep the soil slightly dry. After dividing, the plants should be repotted using humus-rich sandy loam soil.

The planting depth should be such that the pseudobulbs are just buried. Leave a 2 cm rim at the edge of the pot, top with moss or fine gravel, then water thoroughly.

Place the pot in a shaded area for 10-15 days, keep the soil moist, gradually reduce watering, and proceed with regular maintenance.

Orchid Cultivation Techniques

Orchid Greenhouse/Shelter

The orchid shelter or greenhouse should be oriented with its back to the west and facing the east. It’s ideal if the southeast direction is open, and the west is shielded by a high wall or large trees. This arrangement allows for morning sunlight but blocks intense afternoon sun.

The surrounding environment should be clean with a certain level of humidity. It’s important to ensure good ventilation, exposure to dew, shade from intense sun, and avoid smoke.

If constructed on a rooftop or balcony, besides shading from above, curtains should be hung on the northwest side to prevent the setting sun from scorching the leaves in the afternoon.

Potting

The best time for repotting or changing pots is generally in the spring months of March-April or in the autumn months of October-November. Flower pots with a smaller opening, deeper base, and larger drainage holes are preferable.

Wild seedlings freshly dug from mountains should initially be planted in clay pots, as they allow for better moisture evaporation and air circulation, facilitating root growth. After 2-3 years, they can be transferred to finer clay pots or porcelain pots.

Watering

During the peak growth period of the orchid in summer, if it lacks water, its growth is stunted. Orchids prefer conditions that are 80% dry and 20% wet. Watering should be thorough when the soil is dry and reduced when it’s wet. The number of watering sessions should be adjusted according to the potting medium used.

Fertilizing

Farmyard manure is an excellent organic fertilizer, but it should be decomposed for at least a year before use. This fertilizer can be diluted 10-20 times with water before application.

When using chemical fertilizers, it’s crucial to maintain a balance of nitrogen, phosphorus, and potassium and to control concentration levels.

For orchids meant for leaf aesthetics, nitrogenous fertilizers and those containing manganese or magnesium should be avoided as they enhance chlorophyll synthesis.

For floral orchids, especially those bred for larger petals, a slight increase in nitrogenous fertilizer is beneficial.

Pest and Disease Control

• Rust Fungus: This typically appears as raised pustules on the upper and lower leaf surfaces and occasionally on stems, containing yellow, orange, rust-colored, or even purple-black powdery spores. While rust isn’t fatal and doesn’t kill the leaves, it weakens the plant. Infected leaves should be removed, and the plant can be sprayed with a 65% zineb powder solution diluted 500-600 times or a copper-based fungicide.
• White Silk Disease: This tends to occur during humid rainy seasons. Initial symptoms include a white mycelium at the leaf base, leading to root and stem rot. Prevention methods include replacing infected soil, applying a fungicide or lime, and ensuring proper ventilation, light, and well-draining soil. Severely infected plants should be destroyed.
• Anthracnose: This disease can occur throughout the year but is more rampant in hot, rainy seasons. Initial symptoms are brown spots that start from the leaf tips and progress towards the stem. Over time, these spots grow and blacken. The disease can kill the entire plant if not treated. Environment modification combined with periodic sprays of fungicides can control the disease.
• Scale Insects (Orchid Pests): Also known colloquially as “orchid lice”, they proliferate rapidly in warm, humid environments with poor air circulation. During their hatching period, a 1% solution of malathion or a 1500 times diluted 50% sulfoxaflor can be applied. If there aren’t many infected pots, manual removal with brushes can also be effective.