– Schlumbergera (2011)

By Barb Rengers (January 2011)

The Christmas cactus, Schlumbergera, has been a favorite houseplant and among the most widely cultivated cacti for years. Often a single plant is passed down from generation to generation because the cacti are long lived and rather easy to grow.

Hybridization has resulted in the introduction of many new varieties of Thanksgiving, Christmas and Easter cacti. To get them to bloom for the holiday season, they need a little special care.

Most of these plants are native to Central and South America. They are different in all respects from the common desert cacti. The plants, called epiphytes, display two different growth forms and have bird-pollinated flowers.

The Schlumbergera species formerly in Epiphyllanthus (S. microssphaerica and S. opuntoides), have opuntialike stem segments that are either cylindrical or compressed, with the areoles distributed more or less evenly over the entire surface. Those described as Schlumbergera or Zygocactus (S. kautskyi, S. orssichiana, S. russelliana, S. truncata) have flattened young stem segments with areoles restricted to the margins and tips.

They are often found in the forks of tree limbs, where they grow in decayed leaves and other natural debris. Since they are tropical cacti, their culture requirements are totally different from those for true cacti. Following are a few tips on how to care for Schlumbergera and get them to bloom for the holidays.

In September and October, Christmas cactus plants should be kept in a cool room with temperatures around 50 degrees F. It’s also very important that they are kept in a room where no artificial light is on at night.

Proper light exposure, correct temperature and limited watering are needed to produce blooms. During the fall, place the plants in a spot where they receive indoor indirect bright light during the daylight hours but total darkness at night.

Because the Christmas cactus is a tropical plant, it requires watering similar to that for other tropical plants. Water Schlumbergera thoroughly and then allow the top inch of soil to dry before watering again. During the fall and winter months, water less frequently to get blooms.

Christmas cacti require about 50 to 60 percent humidity. A humidity tray is one method of providing this. Fill a waterproof saucer with gravel, then add water halfway up the gravel and place the pot on the gravel surface.

Never place a Christmas cactus near heat ducts or drafty areas. In October or early November, fertilize with a liquid fertilizer, 0-10-10. Make a second application of this fertilizer in February. In the growing season from April through September, fertilize the plants with an all-purpose liquid houseplant fertilizer with a nitrogen content no higher than 10 percent.

It is very frustrating when the flower buds that develop drop off the plants. Bud drop can be caused by several different conditions. Usually it’s because of overwatering, lack of humidity or insufficient light.

After the holiday season, give Schlumbergera a rest. Place them in a cool room and provide limited water. If they lose a few leaves or joints and appear weak during this rest period, don’t worry.

The best time to pinch, prune or shape a Christmas cactus is when the new growth begins in March or early April. The best time to repot is in February, March or April. The plants flower best when pot-bound, so don’t overpot. If a Christmas cactus is given proper care and the right location, it may flower several times throughout the year.

References:
Ed Hume Seeds – www.humeseeds.com
The Cactus Family – Edward F. Anderson
Zygocactus (Schlumbergera) – Mark E. Cobia