Does your Christmas cactus bloom too soon?

by How Does Your Garden Grow? By Sharon Daniels
Thanksgiving cactus on left, Christmas cactus on right. Thanksgiving cactus on left, Christmas cactus on right.

Many of us don’t pay attention to stems when we choose a Christmas cactus, but later we may wonder why it blooms weeks before Christmas.

The easy answer is that two closely-related plants in the Schlumbergera genus are two different flowering cacti: Thanksgiving cactus and Christmas cactus.

An easy way to tell them apart is to look at stems (these plants don’t have leaves). The Thanksgiving one has “teeth” on sides of stem segments, sometimes called “crab claw.” Teeth are soft, not sharp.

On the other, stem segments have scalloped or rounded edges, and stems are narrower.

Another identification method is in pollen of blooms. If yellow, it likely is Thanksgiving cactus, or if pink, Christmas cactus. Also, my Thanksgiving cacti are showing flower buds right now and the others are not.

These familiar plants may be pass-down treasures from one generation to another, or it’s easy to start a new one from your mother or a neighbor. Simply break off a stem segment a few inches long and insert it in damp potting soil. These are truly easy-care houseplants.

Both types grow wild in mountains of southeastern Brazil, so they like shade and cooler temperatures, unlike cactus from a desert habitat.

Both need cool temperatures to spur flower buds, ideally 55 to 60 degrees at night. Flowering is best with a longer period of total dark. Set them in a closet 13-16 hours each night and flowers should follow in about 8 weeks.

If you prefer later bloom, keep them for a longer time in fall in a warm, well-lighted place, such as the room where you spend time in the evening.

If buds drop, it usually is because of a change in environment, especially if you move a plant from cool temperature to a warmer temperature. Don’t put the plant in a draft or near a heat source.

There is no particular reason to prune, but if you want to, do so after flowering end. This forces branching and should give you even more flowers next season.

And if your plant waits until March to show flowers, here’s the rest of the story. There’s another one: Easter cactus.

Sharon Daniels is a Virginia Cooperative Extension Master Gardener volunteer.