"Christmas Cactus" or "Thanksgiving Cactus?"
Before trying to under why your "Christmas Cactus" isn't blooming or figuring out how to force your plant to bloom you have to identify which of the Schlumbergera you're growing. Do the leaves of your "Christmas Cactus" have pointed edges? Do the flowers of the cactus droop down from the ovary like in the picture above? Is it setting buds or flowering in early to mid November? If you answered to all of these questions then you can say with 99% certainty that you are growing Schlumbergera truncata, also known as "Thanksgiving Cactus." As explained in the post, Not Your Grandmother's Christmas Cactus, the true "Christmas Cactus" is Schlumbergera x buckleyi and usually isn't found in big box garden centers and greenhouses for sale around the holidays. It's easier for commercial plant growers to propagate, grow and prepare Schlumbergera truncata to bloom in time for holiday sales. They may even come with a generic "Holiday Cactus" label. A "Christmas Cactus" is easily identified by the segments of the leaves because it doesn't have pointed edges and the blooms don't curve down from the ovary like the "Thanksgiving Cactus."
How to Make Your "Christmas Cactus" Bloom.
The post, How to Make Your Christmas Cactus Bloom, covered the methods indoor gardeners can use to make their Christmas Cactus bloom in time for the holidays. In short: blooms are triggered by the cooler temperatures and longer nights. If you grow your "Thanksgiving Cactus" outdoors during the spring and summer it should naturally start to develop flower buds as summer ends and autumn arrives. If you brought your plant indoors too soon or kept it indoors all year you may still be able to trigger a flowering period in time for the Christmas and New Years. Place the plant in a cool location where the temperatures are around 50 to 55 degrees Fahrenheit. This could be in a separate room, an enclosed porch, a garage, a cool windowsill or a basement. The plant will need darkness for about 12 hours to set blooms, you may have to put your lights on a timer or avoid turning on the lights in the room from the hours of 8pm-8am if it is in a room you use. If the only light your plant receives is natural sunlight from a window the longer night period will happen naturally. Once the flower buds have set on your plant keep it in the same location until they begin to open up. If you move the plant to warm location to enjoy it before the buds have opened the plant may drop all the flower buds and all your work will have been for nothing.
"Christmas Cactus" Cuttings and Pollination.
Propagating succulents is easy-anyone can do it. You can propagate succulents from leaf cuttings and from stem cuttings like I did with the Jades. Schlumbergera being succulents are just as easy to propagate from a cutting you take or from the stems and branches that may naturally break and fall off the plant. Once you have a leaf segment or a stem set it somewhere for a couple of days and allow the cut end to dry and insert it into a pot with a well-draining potting soil mix like in either of the examples linked above. While cuttings are the easiest way too make more plants from your "Christmas Cactus" you can also pollinate the blooms of your "Christmas Cactus" and save and sow the seeds from the fruit that develops.
Even though Schlumbergera truncata is passed off as "Christmas Cactus" by big box retailers and a lot of the times just given the "Holiday Cactus" moniker it is still a nice plant to have around. In my experience these plants take a lot of neglect and still manage to produce beautiful blooms just as we need them most during the early, dark days of winter. You can extend the life of the blooms of your Schlumbergera by keeping the potting soil evenly moist and the temperatures of the room it is residing in on the cooler side. Let the plant dry out too much while it is setting buds or flowering and the buds and flowers may fall off. Don't worry about a few leafs or stems that may fall off of your plant. Take advantage of these pieces of the plant to propagate more plants. If you need an indoor gardening project to take your mind off of winter try your luck at hand-pollinating the blooms.
Used to have a "real" Christmas cactus that came from my grandmother's parent plant years ago, but ... managed to neglect it to death. The leaves are so much prettier than the "crab cactus" as she called the Thanksgiving one.
ReplyDeleteShe believed that a dose of potassium in September was a must. Take a piece of banana peel and throw it into the blender with enough water to make a syrup and give it to the plant. Too late now for this year, but it probably wouldn't hurt.
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thanks for reminding me of a fun plant!
Oh god...you have reminded me of my dead one out back!!! I still have not moved it out, but it is deader than a doorknocker!!! Hey...I am gonna look for a new big full one this year. I think tomorrow may be the day to go shopping! Thanks for the good info and reminder, Mr. BT!!! Hope all is well with you and your world.
ReplyDeleteJulie
Great stuff, MBT.
ReplyDeleteLol, FTW! I keep my house at 58 and don't have a lot of light, even though it is sitting next to the big back window, so I've never had problems with it blooming. Usually around now and again round Easter and sometimes in June, too. Also, entirely theoretically, should you drop the whole damn pot when repotting and break off about a third of the plant... it still blooms on the normal schedule.
ReplyDeleteP.S. My first "real" job in college was as a tech writer for Schlumberger. Or were they Applicon then? Or MDSI?
P.P.S. I deffo have the S. truncata.
thank you for the advice...i going totry this i have beautifu; green cactus- but no bloom in 2 years.... i going to try this closet tip and let you know if it works.
ReplyDeleteI used to have a 'real' Christmas cactus - left it outside too long one year much to my chagrin. A few years ago I got a couple of truncata cuttings that struggled along and grew very slowly. The larger one is finally coming into its own this year and has lots of blooms and buds - yay!
ReplyDeleteI've had my eye out for a replacement Christmas cactus for a few years, still haven't found one around here, although the Thanksgiving ones are readily available.
Thanks for making the distinction so clear. I wonder if the fruit are edible?
ReplyDelete@Garden Faerie, LOL.
ReplyDelete@Anonymous, Make sure you're also fertilizing with a cacti & succulent fertilizer.
@Garden Girl, Yes, S. truncata is a lot easier to source than the real Christmas Cactus. Although, I think I've seen it for sale at Ted's booth at the Chicago Flower & Garden Show.
@Walk2Write, You got me curious, but after Googling I can't find an answer one way or another about the fruit being edible. I'll keep looking.
Hi, Mr. Thumb - Great info here, but I have a question: What is the lowest temp a Christmas cactus can take?
ReplyDeleteI have a HUGE Christmas cactus that I haven't had inside for the last 14 years. It blooms fairly regularly, usually in February, as I don't try to force it to bloom at a specific time, just when Mother Nature says.
Thankfully, I live in the mild climate of the San Francisco East Bay, and the plant has done well in my shaded backyard. However, we are expecting frost tonight and I am a little worried, although the plant is under a low tree. In the past I have covered it with a dropcloth, but was wondering, if we get a hard freeze, if I am in danger of losing this beloved plant. It's very difficult to move as it is pretty big!
This was very helpful! I recently got some cuttings of what must be "Thanksgiving" Cactus."
ReplyDeleteGlad to have found this information! I feel in love with the flowers at first sight(, and my mind said, "Ah, they are cactus; easy for you to maintain. Pick them up, you lazy gardener!"). I have the ones that bloom magenta and white flowers. Both have buds ready to bloom. :-)
ReplyDelete