Christmas cactus. (Photo by Dan Gill)

For Release On Or After 12/13/13

Of the many kinds of plants we use to decorate our homes for the holidays, the holiday cactuses possess a special beauty. And yes, despite the fact that these plants don’t have spines, they are true cactuses.

Unlike poinsettias, which are generally discarded when the season is over, with proper care cactuses will produce their gorgeous flowers for you during the holidays year after year.

The “uncactus” appearance of these plants has to do with where their ancestors live in nature. They do not live in deserts but come from the rainforests of Brazil. There, these plants are epiphytes and spend their lives perched up in trees with their roots in pockets of decaying organic matter lodged in cavities along branches. This explains much about how we need to care for holiday cactuses to keep them healthy.

The original species used to develop holiday cactuses are Schlumbergera truncata, the Thanksgiving cactus, and Schlumbergera russelliana, the Christmas cactus. The Thanksgiving cactus is distinguished by sharp teeth-like edges on the flat stem joints, while the Christmas cactus has rounded scallops on the edges of its flat stems.

Breeders, however, have crossed these species together so the plants you purchase these days are not true Thanksgiving or Christmas cactuses but are generally hybrids of the two and have teeth, rounded scallops or something in between. For this reason we have adopted the name “holiday cactus” to refer to these plants that will bloom anytime from November through January. Breeding has produced more robust, upright plants that are easier to grow with larger flowers in a greater color range.

Choose a holiday cactus that has flowers the color you prefer, such as red, magenta, pink, rose, lavender, white, salmon, pale gold or orange. It should have mostly large buds that are showing color and a few open flowers.

It is very common for young flower buds to drop from a plant once you get it home, primarily because of rapid changes in the plant’s growing conditions. Place your holiday cactus plant in a brightly lit location, such as by a window, so that it gets plenty of light. Avoid heat sources, and choose a location that tends to stay cooler, especially at night. Also, don’t allow the plant to dry out when it is in bloom or buds will drop.

Water the plant often enough to keep it evenly moist (generally, water when the surface of the soil feels dry). Each flower generally lasts about five to seven days, and the plants remain in bloom for two to three weeks.

After flowering is finished, allow the soil in the pot to feel dry when you stick your finger in it before watering. If you displayed the plant in a location other than a bright window, move the plant to a window. There is no need to fertilize.

Care after the holidays

Come spring, you may continue to grow your plant indoors or move it outside for the summer. When placed outside, the plant may receive some morning sun, but keeping it in shade for most of the day is preferred.

Do not keep the soil too moist. The result of excessive watering is root rot, the most common cause of people killing these plants. You can help reduce the chances of overwatering by growing your plants in loose, fast-draining potting soil rich in organic matter. Fertilize your plant with your favorite slow-release or soluble fertilizer following label directions.

These plants prefer to be pot bound (remember, they live with their roots confined to small pockets of organic matter in their natural habitat). Only repot your plant if it is no longer stable in the pot it is currently growing in and tends to constantly fall over. Then, choose a pot only slightly larger than the one in which it was growing. To help with the stability of these sometimes-top-heavy plants, you can choose to grow them in heavier clay pots rather than plastic, although either works well.

Getting them to bloom

Holiday cactuses are triggered to bloom by long nights over 12 hours long and/or chilly nighttime temperatures below 65 degrees. This is easily achieved by leaving or placing your plant outside in late September where it will receive naturally long nights (do not place the plant in a location where porch lights, flood lights or street lights shine on it) and chilly night temperatures in October and early November. Bring the plant inside if nighttime temperatures will fall below 40 degrees.

Beginning about September, allow the soil to dry out more before watering and stop fertilizing. When you begin to see the little buds forming at the tips of the branches, water often enough to keep the soil evenly moist, but do not keep it constantly wet.

Move the plant indoors when the buds are about an eighth of an inch long and place it in a window for display. If the branches are pendulous and hang down, boost up the pot so the branches hang gracefully.