A Christmas cactus (Schlumbergera) in full bloom is a majestic sight, the bold, bright blossoms and unusual foliage make for an eye-catching display.
While I find the plants attractive even when they aren’t in bloom, what I really want are those beautiful flowers!
Whether you’re growing your holiday cactus indoors or out, there might come a time when the plant decides not to bloom.
It’s usually a sign of stress, but a failure to bloom can also mean that the plant is being treated too well! Schlumbergera cacti need a little neglect and a quiet period to go into dormancy before they’ll flower.
To be completely clear, I don’t do anything special with my Christmas cacti and they all bloom and rebloom without any help.
But I’m lucky enough to have the right amount of natural light and temperature fluctuation from summer to winter which they need.
Whether you want to ensure your cactus flowers or you’re dealing with a specimen that isn’t putting out blossoms and you want to figure out why, this guide will help!
Here’s what we’ll cover to make that happen:
What You’ll Learn
Keep in mind that this information applies to all of the holiday cacti, not just Christmas cactus (Schlumbergera x buckleyi).
If your Easter (Rhipsalidopsis gaertneri) or Thanksgiving cactus (S. truncata) isn’t blooming, the same steps will help you troubleshoot and resolve the problem.
Any of the plants in the Rhipsalidopsis and Schlumbergera genera and their hybrids are addressed here, collectively known as holiday cacti.
In ideal conditions, a holiday cactus will grow long branches made up of flattened segments called phylloclades or cladodes.
At the end of these emerge colorful flowers in shades of pink, red, white, and yellow.
The time of year that these blossoms emerge depends on the species.
Thanksgiving types typically bloom around the end of November, the Christmas types around mid-December, and the Easter types in the late winter or early spring. Though this can vary.
Many stores just label all of the holiday plants as “Christmas cactus,” and our guide to the different types of holiday cacti can help you learn more about the differences.
The first cause of a lack of blooms is a common one:
1. Insufficient Light
While direct sun all day is far too much light, a lot of indoor gardeners put these plants in too little light.
Bright, indirect light is ideal, but focus on the “bright” part of that phrase.
The dappled shade of the great outdoors, where they would be found in nature, is a lot brighter than a corner in a room with north-facing windows.
Near a south- or west-facing window but out of direct light is ideal. Or a window with a tree outside that blocks some of the afternoon sun. Some direct light in the morning will even be welcome.
If you aren’t sure how much light your houseplant is receiving, grab a light meter.
You can usually find meters that combine moisture and light measurements so you also be sure you’re providing enough of both.
In general, if the plant isn’t blooming it’s often as a result of lack of light.
If you want to move your specimen to a spot with brighter light, do it gradually as a sudden change in lighting conditions can risk burning the foliage, causing yellow or brown leaves.
2. Over- or Underpotting
These plants like to be a little bit rootbound but not overly crowded. If the houseplant is in a container that is too small or too large, it might not flower.
Ideally, the pot should be about the same size as the root ball or just a smidge larger.
If the container is significantly larger than the roots, remove the plant, brush away the soil from the rootball, and repot in a smaller container.
On the other hand, if it is rootbound and you’re seeing roots coming out of the drainage holes, repot into a container that is one size up.
You can learn how to repot a Christmas cactus here.
3. Pests or Disease
Christmas cacti are pretty tough.
I’m scraping mealybugs off my orchids and scale insects off my staghorn ferns like it’s my full time job, all while repotting droopy philodendrons that I accidentally overwatered.
But my various holiday cacti are just bopping along without any problems.
Still, that doesn’t mean diseases and pest infestations can’t happen and if they do, it can cause a failure to bloom.
Aphids, fungus gnats, mealybugs, scale, spider mites, thrips, and whiteflies all feed on plants in the Rhipsalidopsis and Schlumbergera genera.
Learn about these pests and how to get rid of them in our guide to Christmas cactus pests.
Diseases like bacterial soft rot, damping off, and fusarium wilt are the most common ones you may encounter with your houseplant.
You can learn about all of these in our Christmas cactus growing guide.
4. Temperature Issues
One of the challenges with growing houseplants is that they live in a sort of perpetual spring.
They have no idea if it’s spring, fall, winter, or summer because the light and temperatures are generally pretty consistent.
The problem is that some plants, like Christmas cacti, need a dormant period to be able to flower.
Temperature is an important part of signaling to the plant that it’s time to flower.
If you tend to let your home stay cooler in the winter than in the summer, it’s all good.
But if you keep your house exactly 72°F year-round, your Christmas cactus isn’t going to receive the dormancy signal it needs to bloom.
What you can do is move the plant to a cool area with temperatures in the high 50s or low 60s to mimic the change in weather that would happen in its natural environment.
That might mean keeping it in a basement with supplemental lighting or popping it outside if the weather is amenable.
They need exposure to these temperatures until the buds start to form, and you should plan to do this every year about a month or two before you want the flowering to start.
Those growing outdoors should be exposed to the appropriate change in temperature and light naturally, so you usually don’t need to worry about those quite as much.
5. Overfertilizing
During dormancy, the plant shouldn’t be given any fertilizer.
Supplying nutrients in the dormant season encourages growth, and that’s not what we want. The dormant period is very important for to the plant’s ability to set buds.
Don’t even side dress with compost or manure. We want the plant to go to sleep and feeding it is akin to giving a kid a bunch of candy right before nap time.
So, stop feeding altogether in the fall or even late summer for types that bloom in November.
Learn all about when and how to feed a Christmas cactus here.
6. Too Much Light
Christmas cacti are daylight dependent, which means they need a certain number of daylight hours to trigger flowering.
They are what is known as “short day” plants that need a shift to shorter days and cooler temperatures than they’ve been experiencing to start the development of flowers.
If you rely on natural sunlight to supply your plant with what it needs to grow, you might already be taking care of the light element.
But if you use supplemental lighting, the plant might not be exposed to the changing light conditions that it needs.
While you don’t necessarily have to put it in complete darkness during the night to encourage flowering, you can do this if you want.
Put the plant somewhere completely dark like a closet for 14 to 16 hours each night.
Better yet, turn the lights off and close the blinds in the room where the plant is growing rather than moving it.
As soon as you see flower buds developing you can stop moving the plant or worrying about making the space dark.
7. Water Issues
Too much water, especially when the plant is dormant, will cause stress, and stress can inhibit blooming.
In the month or two before your plant should be blooming, be sure to reduce the amount of water you give.
The soil shouldn’t be allowed to dry out completely, but you should be watering less often than you would during the growing season.
Not only is the plant not putting out new growth temporarily, but with the cooler weather and lower light of the fall and winter seasons, there is less evaporation happening.
Bring On the Bloom Bonanza
If you’d like to trick your plant into blooming at a different time of year, you can do that.
Give it the recommended light and temperatures as described above, and it will start flowering.
All those Christmas cacti you see in full bloom during the holiday season?
Those are encouraged to bloom by growers changing their environment to ensure that they are flowering as the plants go on the shelves.
Is your holiday cacti not flowering when it’s supposed to? What do you suspect is the issue? Let us know in the comments section below!
And for more information about growing Christmas cacti, check out these guides next:
