Schlumbergera bridgesii is the proper name for the well-known forest cactus, or Christmas cactus. As its common name implies the Christmas cactus flowers in mid-winter. Though some do flower for Christmas, the natural flowering season for others comes later. This member of the cactus family is native to the tropical jungles of Brazil and is epiphytic, attaching itself to trees that grow on mountains up to 4800 feet. They prefer darker, wetter conditions than the desert cactus, and need peat-based, soilless mixes, and year-around watering. Generally these plants are treated like ordinary house plant.
There is a lot of confusion surrounding the holiday cacti; Christmas cactus, Thanksgiving cactus, and Easter cactus. The easiest way to tell the difference is by looking closely at the leaves. Christmas cactus leaves are smooth with scalloped edges. The Thanksgiving cactus has more-pointed teeth along the edges of the leaves. The Easter cactus has a thicker, slightly more upright leaf and often has a purple or maroon color along the leaf edge. Easter cactus also has brittle-like hairs, often called cat whiskers, at the stem joints. These sound like hard and fast rules, but unfortunately there are a lot of crosses that can make it hard to distinguish between many of the new hybrids. Fortunately each cactus plant produces beautiful, colorful blooms, and can last 50 years or more.
The Christmas cactus likes bright conditions but not direct sun. It needs watering about once every three weeks in midwinter and an increase in the frequency of water as summer approaches. If it is budding, or in bloom, give the cactus a little extra water.
To bloom, many of the forest cacti need cool nights as close to 50 degrees as possible. A few forest cacti are also triggered by the length of the night, as long as they are in a place that gets uninterrupted periods of darkness. If lights are turned on regularly, it might cause some confusion, but if you have continuous cool nights, then the length of the night is a secondary concern. After they bloom, treat these plants more like a desert cactus, with more infrequent watering until summer.
Caring For Your Forest Cactus: We have already talked about light, temperature, soil and watering, so let’s touch on feeding, repotting, cleaning, and pest control.
Feeding: Use high-potash fertilizer once a month in the spring, summer and autumn. Do not feed while flowering.
Repotting: Repot each year into next-size pot, handling the root-ball carefully because they dislike having their roots disturbed. The base of the plant becomes woody with age, and it is a good idea to propagate new plants. Approximately one month after flowering, take cuttings of two segments, cutting at the joint with a sharp knife. Dust both cut ends with hormone rooting powder containing fungicide and let dry for two days. Place end of cutting gently into almost dry soilless mix, planting about 1/2 inch deep. Then water after two weeks.
Cleaning and pests: Spray at least once a week to keep your plant fresh and dust free. Add an insecticide to the water 2 to 3 times a year to combat pests as well as a systemic fungicide to prevent the orange and brown spotting that sometimes affects them.
For FREE Mother Lode Gardening advice, contact a Master Gardener at the University of California Cooperative Extension at 209.533.5912, or email firstname.lastname@example.org . Happy Holidays from our homes to yours!
Betty Hensley is a University of California Cooperative Extension Master Gardener of Tuolumne County.