Thanksgiving cactus (Schlumbergera truncata) and Christmas cactus (Schlumbergera bridgesii) are popular holiday plants. Both produce showy blooms in shades of pink, orange, lavender, rose and red in late fall or winter. Although similar in appearance, the two bloom at different times, giving rise to the popular names of Thanksgiving and Christmas cactus.
The primary difference between the two is the shape of the fleshy sections of the stems, called phylloclades. The edges of the stem segments on a Thanksgiving cactus are serrated and have tiny points along the sides and tip. The Christmas cactus on the other hand has elongated segments with smooth edges and a rounded tip. Both produce flowers on the tips of the stems.
Thanksgiving and Christmas cactus require the same basic care and will thrive for years.
- Light: The Thanksgiving and Christmas cactus prefer bright, indirect sunlight during the spring and summer when the sun’s rays are most intense. They can tolerate more direct sunlight during the fall and winter, but watch them closely for any signs of sunscald. These plants are native to Brazil and typically grow in the understory of rainforests where they receive filtered light.
- Blooming: To initiate blooming the plants need 12 to 14 hours of darkness a night, beginning by the middle of September. New buds form in 3 to 6 weeks. Once the buds have formed, the plants no longer need lengthy periods of darkness each night.
- Temperature: During the spring and summer, these plants prefer temperature between 70 and 80 degrees Fahrenheit. However, they require cool temperatures to set the buds in the fall. Temperatures above 90 degree will cause buds to fall.
- Watering: During the growing season, these plants tolerate soil that dries out between waterings, but once buds are formed, they require evenly moist soil. If the soil is allowed to dry out, the plants drop the buds and cease blooming.
- Fertilizing: Fertilize your cactus once a month from spring until late summer with one-half strength water-soluble plant food, such as 20-20-20 or 20-10-20, says the Clemson University Extension. Stop applying fertilizer by late August to encourage good bud formation. A monthly application of Epsom salts mixed to a rate of 1 teaspoon per gallon of water also provides your cactus with the magnesium it needs to thrive, says Clemson.
- Soil: Mix one cup of perlite to three cups of potting soil to make a suitable soil for your cactus. These plants require loose well-drained soil with adequate aeration.
- Propagation: Thanksgiving and Christmas cactus are easy to propagate from stem cutting. Pinch of sections that contain three or more nodes. Allow them to callous for a day or two by placing them in a shady, dry area. Insert the cuttings in the soil to a depth of one inch and keep the soil moist until news roots form. You may wish to dip the ends in rooting powder to speed the process, but it is not necessary. Repot your plants every three to five years, or whenever it becomes root bound.