How to cultivate crab claw cactus to produce a top-quality specimen

The crab claw cactus (Schlumbergera truncata) is an epiphytic succulent plant from the tropical rainforest. Its leaves have degenerated into flat, leaf-like modified stems that perform the function of leaves. On each side of the stem there are 2 to 4 coarse teeth; the stem has no spines, but branches profusely and droops downward, with the stem segments linked together in a shape resembling a crab's claw, hence its name. Flowers bloom at the tip of the stem; the flowers have no stalk, are funnel-shaped and double-petaled, with each pair of petals symmetrical and curling backward outward. Flower colors include deep purplish red, rose red, pink, yellow, white and so on. Some bloom before New Year's Day, and some bloom during the Spring Festival, with a flowering period lasting 30 to 40 days. A three-year-old grafted crab claw cactus, properly shaped and supported, can reach a crown diameter of 70 to 100 cm, with stem segments hanging upside down outside the pot, dotted with red flowers amid the emerald green, and can open 200 to 300 flowers at the same time, which is very spectacular. In the cold winter season, it is truly an excellent ornamental, deeply loved by flower enthusiasts.

Although the crab claw cactus belongs to the cactus family, it differs in many ways from the various cacti people commonly see. It prefers shaded, ventilated and humid environments, and fears both heat and cold. Direct scorching sunlight or rain will harm it. Under dry, hot and stuffy conditions, it will not only grow poorly but also fail to bloom, and will attract red spider mite damage. The potting soil is best as fertile, loose, humus-rich, slightly acidic soil. The management priorities for the four seasons are as follows:

(1) Spring management: After the winter flowers fade, promptly cut back at the 3 to 4 stem segments below the spent flowers, and at the same time thin out some old stems and overly dense stem segments, so as to shape the plant and improve ventilation. After blooming in March, there is a short dormant period, during which fertilizer should be stopped and water controlled, until new buds emerge from the stem segments, then normal water and fertilizer management can resume. Watering frequency should increase as the temperature rises; do not water until the potting soil is dry, and keep it moist. When the air is too dry, you may spray the stems and leaves appropriately. Apply dilute nitrogen fertilizer once every 10 to 15 days, during March to April. To facilitate drainage, first fill the bottom of the pot with a layer of small stones about 3 cm, then cover with soil and add base fertilizer; the base fertilizer is best as well-rotted poultry manure rich in phosphorus. Cover the base fertilizer with a thin layer of soil before planting the seedling. Use slightly acidic culture soil for planting; do not use alkaline soil.

(2) Summer care management: The crab claw cactus can grow slowly at 15°C; when it is around 25°C and the air is relatively humid, it grows faster; when the temperature exceeds 30°C, even in a shaded environment, its growth rate gradually declines and it enters a semi-dormant state. At this time the crab claw cactus should be placed in a cool spot under a shade awning on the balcony, or hung in a ventilated indoor spot, to protect it from scorching sun and rain. Spray water frequently to increase humidity and lower the temperature. If it is even slightly exposed to sunlight, or placed in a stuffy hot location, the plant will be scorched, causing the stem segments to yellow, wilt, drop off and die. In summer, watering must not be excessive, and fertilizer must not be applied, otherwise it will cause root rot and death.

(3) Autumn and winter care management: In early autumn the temperature is still high, so spraying the leaves and sprinkling water in the environment should continue. From September onward, the climatic conditions gradually become suitable for the growth of the crab claw cactus. In mid-to-late September, as the temperature drops, sunlight can be given in the morning and evening. In mid-to-late October, full sun should be given to promote flower bud differentiation and produce more buds. By early-to-mid November, as the temperature turns colder, the crab claw cactus should be brought indoors to overwinter, and placed in a spot with ample sunlight. However, during the flowering period, direct sunlight should be avoided to prolong the flowering period. Watering in autumn should be moderate; the potting soil should still be kept moist, neither dry nor waterlogged. Too dry, too wet, or too great a day-night temperature difference will all cause flower and bud drop. In winter the temperature is low, so the evaporation of the crab claw cactus decreases accordingly, its growth slows down, and its water requirement is smaller, so even more care must be taken not to water too much. Excessive watering in winter will lead to root rot and death. In autumn and winter, as this is the period when the crab claw cactus forms buds and blooms, apply a phosphorus-rich top-dressing liquid fertilizer once every 7 to 10 days; do not fertilize during the flowering period. Winter temperatures change easily, so good work must be done on heat preservation and ventilation. When the room temperature drops to 5°C, protect against freezing. To make the crab claw cactus bloom on schedule in winter, the room temperature must be kept at around 15°C, otherwise even with a pot full of flower buds, it will be difficult for them to open.