How to Get Christmas Cactus to Bloom at, Lets Say, Christmas
I have a “Christmas” cactus blooming right now, the first day of spring 2019. I’m embracing the blooms and calling it my Spring cactus although there are different Schlumbergera plant relatives, one that is currently a Thanksgiving cactus called a Christmas cactus; the original Christmas cactus (in photo) no longer on the market and an Easter cactus that is not even related.
These hardy but tropical plants need a little help to bloom on cue here in North America. Back in their native habitat in Brazil, they have weather triggers to get them to bloom in December, the beginning of the South American summer. I grew up near their native habitat, Christmas without swimsuits still seems a little odd to me but now I’m happy just unwrapping them as a gift and staying bundled up in my coat and blankets.
Most cactuses sold on the market today are actually Thanksgiving cacti, which explains why they tend to bloom end of November. They are also grown in greenhouse conditions to get them to set bud for sale around Thanksgiving.
To determine what kind of cactus you have, look at the green fronds. The original Christmas cactuses (Schlumbergera bridgesii) have smooth, round edges (photo) while Thanksgiving cacti (Schlumbergera truncata) have pointy, jagged ones.
Like other succulents, cacti are well-adapted to life with little precipitation. The leaves have evolved into spines, which in addition to allowing less water to evaporate than regular leaves, defend the cactus against water-seeking animals. Photosynthesis is carried out by enlarged stems, which also store water. Unlike many other succulents, the stem is the only part of a true cactus where this takes place.
My Thanksgiving cactus started to bloom because I had it outside on my back porch earlier this fall. The cooler temperatures triggered the buds to form without my doing any adjusting to the amount of light it was getting every day.
Holiday cacti are called "short day plants" meaning in order to produce flower buds, they require fewer daylight hours and/or cool night temperatures. The shorter days and cooler nights signal the plant to produce buds. I have tried both triggers and found the cooler temperatures are the easier way to encourage blooms.
To get your holiday cactus to bloom when you want the blooms, locate holiday cacti indoors in a cool, bright location where daytime temperatures are 65-70° F and evening temperatures are 55-65° F. If plants are exposed to cooler night temperatures of 55° F, plants will bloom in approximately 5-6 weeks, sometimes regardless of the day length.
I frankly don’t mind when they bloom out of season, it reminds me of how I enjoy my “Let it Snow” Lap Quilt Throw after Christmas as well. I just love having them in bloom any time they decide the time is right.
Happy Christmas in March!