Timing is everything with these flowering succulents.
IF YOU WANT to look like a green thumb when it comes to growing colorful blooming houseplants, try a Thanksgiving or Christmas cactus (Zygocactus truncatus).
Unlike desert cactus, these succulents feature a trailing habit. They grow as epiphytes among tree branches in South American rain forests and require different care than their spiny cousins. Highly popular as holiday plants, they are capable of producing long-lasting, colorful flowers in red, rose, purple, lavender, orange and white.
Generally, all that’s required for them to thrive is a brightly lit location out of direct sunshine (such as an east-facing window), moderate water, and a monthly application of a half-strength dilution of soluble houseplant food during spring and summer. They’re more likely to bloom if they’re a bit root-bound, so don’t be in a big hurry to repot them into bigger containers.
Although forest cactuses are prolific bloomers, they often flower at odd times, and it can be difficult to persuade them to blossom on time for the holidays. There are two methods that can help with timing: The first is to take advantage of the natural tendency of these plants to set buds during periods when days are shorter. Put your forest cactus in a dark closet for 14 hours a night, starting six to eight weeks before you want it to bloom. Bring it back out into a bright location during daylight hours. Once buds begin to form, the closet treatment is no longer needed, and the plant should bloom beautifully for the holidays.
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The problem with this method is that if you’re a dim-dim like me and forget the plant is in there and open the door, it’s back to square one if any light hits the plant. You’ll have to restart the entire process, and wait another six to eight weeks for the buds to form.
The other method eliminates the need for nighttime darkness. Starting in late September or early October (I know; too late this year), keep the plant in a brightly lit backroom where nighttime temperatures can be kept between 45 and 55 degrees. Water very sparingly, until buds begin to form. Once the buds form, you’ll want to keep the plant in slightly warmer conditions, so water normally, and keep nighttime temperatures above 55 degrees. Wait until the plant is in full bloom before moving it to a different location for display purposes.
If you move it before the flowers open, the buds might fall off, which definitely makes for a less-than-cheery holiday display.
If you find it difficult to maintain the required cool nighttime temperatures, I recommend marrying a Canadian woman. I’ve learned from experience that Canadians not only sleep with the windows wide open in the middle of winter, but have a fan blowing, as well (which is scary, because when I was a kid, my Grandma Maude O’Hara told me that if you go to sleep with a fan blowing on you, you’ll wake up dead!). Fortunately, I’ve managed to survive, and I have to say my Christmas cactus have bloomed right on schedule every year since my wedding 35 years ago.
For extra fun, try growing fruit on your holiday cactus. You just need at least two plants with different-colored flowers in bloom at the same time. Pick a flower off one plant, and use it to pollinate about five blossoms on another plant by wiping the pollen-covered stamens against the pistil (the flower part that sticks out the farthest).
If all goes well, a colorful, inch-long berry will develop at the base of the pollinated flower. The fruit usually remains decorative for a year or two. When the fruit begins to soften, harvest the berries, squish the pulp within onto a paper towel and allow it to dry. Gather up the tiny black seeds, and germinate them in a seeding mix under a grow light. It’s always a fun surprise to see what color flowers the new Christmas cactus seedlings will produce.