Christmas cactus (Schlumbergera bridgesii) is an old-fashioned plant that your grandmother may have grown. It is characterized by glossy, flat, chain-like segments and forms a pendant (flower) that is usually red or reddish-orange. Christmas cactus is an epiphyte, which means in nature it grows hanging from trees in tropical forests.
As a houseplant Christmas cactus does best in course, porous soils high in organic matter. Use half sand and half fine bark or course peat moss. Provide excellent drainage and allow plants to become somewhat drier between watering just prior to bloom. Fertilize every two-to-four months with a standard balanced houseplant fertilizer when plants are actively growing. Place it away from doorways, heating vents or other drafty locations. And Christmas cactus blooms best if kept somewhat pot-bound.
Difficulty in getting Christmas cactus to re-bloom is a frequent complaint. Because they are short-day plants, one sure way to form buds is to subject them to total darkness from 6 p.m. to 8 a.m. beginning September 1 until buds form. If keeping them in total dark at night is difficult, there's another option. At temperatures around 55 degrees or slightly lower, Christmas cactus loses its short-day requirements for flower bud setting. If you leave plants outside until frost threatens, they should have a nighttime temperature of 45-55 degrees for four weeks, which should encourage buds. Be sure to bring them inside before a frost.
You can start new plants after blooming season by cutting three-to-four inch segments and inserting them in moist sand. Repot once the roots are visible.
Barbara Mole, Smith County Master Gardener
Texas Cooperative Extension
December--February: When the cactus has finished flowering, it needs about two months' rest. Give it almost no water or fertilizer at this time. March-May: The cactus will begin to grow, with sprouts appearing at the tips of joints. Begin to water and add a small amount of diluted fertilizer. This is the time to repot if necessary.
June-July: The plant needs a second rest period. Water sparingly and do not fertilize, but do not let the soil dry completely.
August-September: Increase watering; never let the plant dry out. Flower buds will begin to form. Keep the plant in one place, as drafts or sudden changes in light may cause the buds to fall off. Give very large plants a little fertilizer now. Flowers will form on healthy shoots. Lifespan: This cactus can live for many years and grow quite large.
Molly Johnson, Smith County Master Gardener
Texas Cooperative Extension
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