Chinese Cymbidium

About

Chinese cymbidium has been grown in China for well over a thousand years, valued less for showy colour than for its grace and, above all, its scent. From a clump of rounded pseudobulbs rise arching, strappy, dark green leaves, and in winter it sends up slender spikes of small, elegant flowers in deep maroon, bronze or green, often almost black, that have a rich, sweet fragrance valued in the classical Chinese tradition of orchid growing.

It is a cool-growing orchid from the woodlands of eastern and Southeast Asia, growing in leaf litter and on shaded banks, so it needs bright indirect light, an open, free-draining root run and even moisture in growth. Its one firm rule is a distinct cool spell in autumn, with cooler nights, to set its flower buds, without which it grows well but seldom blooms.

Grown in an open orchid or terrestrial-orchid mix, kept cool and bright with even moisture and a cool autumn rest, it can be long-lived. It suits a cool, bright room or a frost-free greenhouse better than a warm living room, and the cooler treatment helps produce its winter fragrance.

Appearance and character

The pseudobulbs are rounded and clustered, each carrying several arching, strappy, dark green leaves, so the plant forms a bold, grassy clump.

The flowers are small and elegant, in deep maroon, bronze, green or near-black, borne on slender upright to arching spikes in winter, and richly fragrant.

It is grown in the classical Chinese tradition as much for its scent and form as for colour, unlike the large, showy florist cymbidium hybrids.

It grows cool and evergreen, keeping its leaves, and needs a cool autumn spell instead of a hard dry rest to set its flowers.

Where it is from

Cymbidium sinense grows in the woodlands of eastern and Southeast Asia, in leaf litter and on shaded banks in cool, bright, humid conditions. It is a plant of cool, shaded woodland instead of warm lowland forest.

Give it bright indirect light, an open, free-draining root run, even moisture in growth, and a distinct cool autumn spell to flower. It tolerates cool but not hard frost, and rots in heavy, wet, airless compost.

How it grows

It grows through spring and summer, building its pseudobulbs and leaves, then, cued by a cool autumn, sends up its fragrant flower spikes in winter. Cool, bright conditions and that autumn chill are what bring the flowers; a consistently warm plant grows well but seldom blooms.

Grow it in an open, free-draining orchid or terrestrial-orchid mix in a pot, and keep it evenly moist in growth, letting it dry a little in winter, using rainwater. Give it a cool autumn spell, with cooler nights, to set buds.

Give it bright indirect light, cool to warm conditions, and average to high humidity, and keep it above about 5 deg C. Repot when the mix breaks down or the clump crowds the pot, ideally after flowering.

Propagation is by division of the clump, keeping several pseudobulbs to a piece, after flowering.

Through the seasons

Spring starts strong growth. Repot if needed, resume feeding, and keep it evenly moist and bright.

Summer is the main growing season, and it can stand outdoors in bright shade. Keep it evenly moist and feed at half strength.

Autumn is the important cool spell. Give it cooler nights and bright light to set the flower buds, and ease off feeding.

Winter is when the fragrant flowers open. Keep it cool and bright, a little drier, above about 5 deg C, and enjoy the scent.

Care difficulty

Moderate, and long-lived, given cool, bright conditions and the important cool autumn spell. It grows readily in an open mix with even moisture, and its main quirk is that it needs cool autumn nights to flower, without which it stays leafy. It rots in heavy, wet, airless compost, and it needs cool instead of warm rooms, which suits a cool sill or a frost-free greenhouse.

Watering

Keep the plant evenly moist through the growing season, using rainwater, since it comes from cool, humid woodland, and let the open mix dry only a little between waterings. Let it drain freely and never sit wet.

Ease off a little in winter, keeping the mix slightly drier while the plant flowers and the light is low, but do not let it dry out hard. Hard water leaves salts and marks, so soft water suits it.

Warning signs, diseases and pests

Heavy, wet, airless compost rots the roots, shown by soft, blackening roots and a loose plant. Repot into an open, free-draining orchid mix, water more carefully, and keep it cool and airy.

Scale insects and mealybugs settle on the leaves and pseudobulbs and can be wiped off and treated with horticultural oil. Failure to flower almost always means the plant had no cool autumn spell.

Brown leaf tips can follow hard water or dry air; use rainwater and raise the humidity a little.

Growing environment

Bright indirect light suits it, out of direct sun, which scorches the leaves. It flowers best in good light and performs poorly in deep shade.

Cool to warm conditions suit it, with a distinct cool autumn spell to flower, and it needs average to high humidity. It is happier in a cool, bright room or a frost-free greenhouse than a warm living room, and it can summer outdoors in bright shade. Keep it above about 5 deg C.

Grow it in an open, free-draining orchid or terrestrial-orchid mix in a pot in bright indirect light, cool and humid, with a cool autumn rest.

Feeding

Feed fortnightly at half strength with a dilute orchid feed through the growing season, since orchids dislike strong fertiliser. Flush the roots with plain water now and then to clear salts.

Ease off in autumn and winter, and resume as growth strengthens in spring. A balanced feed suits it, with a higher-potassium feed as buds form if you wish.

Troubleshooting

It grows well but never flowers. It has had no cool autumn spell. Give it cooler autumn nights and bright light to set the flower buds, since warmth alone keeps it leafy.

The roots have gone soft and black. Rot from heavy, wet, airless compost. Repot into an open, free-draining orchid mix, water more carefully, and keep it cool and airy.

The leaf tips are browning. Hard water or dry air. Water with rainwater and raise the humidity a little.

Can I grow it in a warm room? It prefers cool, bright conditions and needs a cool autumn to flower, so a cool sill or frost-free greenhouse suits it better than a warm living room.

Is it safe around pets? Yes. Cymbidiums, like other orchids, are not listed as toxic, so it is safe with cats, dogs and children.