Written by s • Flower Your Christmas Cactus – Guaranteed!

The Christmas Cactus is also called Holiday Cactus and Thanksgiving Cactus. It’s a familiar sight in the holiday season and through the early part of each year. The unique flowers have whorls of petals, like skirts, and the bright colors of pink, red or orange (and sometimes white) are incredibly cheerful and ‘holiday appropriate’. No wonder they are such big sellers, and seem to end up in the houseplant collection of nearly everyone.

Trouble is, although they will grow in the house, and develop pretty quickly into an attractive plant with arching and hanging stems, the almost never flower, so after a while you might start to ask yourself, “ Why am I growing this plant?” or, “Help, I can’t get it to bloom again!”

OK, don’t worry, because the non-flowering days of your big ol’ Christmas Cactus are over. From now on, if you follow the simple directions below, you are going to have a great plant in bloom, ready to splash all over your social sites – and get lots of upticks!

Before letting you in on the secret, though, let’s look a bit more closely at this fascinating and strange plant. If you aren’t interested in all that stuff, just jump down the page, but hey, you are missing out on some cool stuff.

The Christmas Cactus

Come with me on a trip to the coastal mountains in the south of Brazil. Let’s trek through the jungle, and blow our minds on all the amazing plant life. Here we are – neat, huh?

The first thing we will probably notice, in this land of warmth, humidity and frequent rain, are all the plants growing on the trees. From humble lichens, mosses and ferns to big bromeliads like these ones.  If you look near the top on the left, you can see some broad, arching stems. Those are not Christmas cactus, but close relatives, probably orchid cactus, Epiphyllum.

But here is the one we want – a wild Schlumbergera species growing as it want to, right on the side of a tree.

How cool is that?

As for what species your Christmas cactus is, it’s hard to say. We have chosen to use the name of the original, first and true one, Schlumbergera x buckleyi. That plant is a hybrid of two other species, Shlumbergera russelliana and Shlumbergera truncata. It dates back to the 1840s, if you can believe it, created at a nursery in England. That plant is actually rare today, and most of the plants being grown today are Schlumbergera truncata (also called Schlumbergera bridgesii), which is the ‘true’ Thanksgiving cactus. Whatever name you give them, they are all similar, and need the same conditions, so enjoy.

These plants are not like most cactus at all. They don’t live in hot, dry, sunny desert, but in the shade of trees, in a region that is mostly wet and hot. They are epiphytes, living up in trees, in pockets of plant debris and live mosses. The stems have been modified by evolution to do all the work of leaves, and they look ‘leaf-like’ too. They are called phylloclades. That’s why the flowers seem to grow right off the green ‘leaves’ – something that would actually be impossible. Flowering takes place in winter, with blooms growing at the ends of each stem, and often along the sides as well.

The Life Cycle of Christmas Cactus

In those mountains of south-eastern Brazil, the climate is seasonal, not year-round hot. Summer, which is in the southern hemisphere, and so from November to February, is hot, with lots of rainfall. Winter – our July and August, is both cooler, and drier. Plants we grow have been adapted to our cycle, so our winter is their winter, and it’s when they bloom – if you do the right things.

You can see from this that the trigger for forming flower buds is cooler weather and shorter days – fall.  So if you live somewhere there is no real frost, just grow them outdoors and they will bloom away each year. Most of us don’t, so now, having kept you waiting all this time – here it is! How to guarantee your Christmas Cactus will flower.

Flowering a Christmas Cactus

From spring to early fall keep your Christmas cactus around 70 degrees. In summer it might be happy outdoors. Water and fertilize it regularly, and don’t cut the branches. Use a regular houseplant fertilizer at half-strength, every 2 weeks. Something for flowering plants would be good, but any regular food will work fine. Water once the soil is dry – picking it up is a good way – if it feels light since you last watered it, it’s time to do it again. Now it’s true that the gradual shortening of the days and reducing water supply are the natural triggers, and if we could do all that, it would be fine. But in a house or apartment, that isn’t practical.

Luckily for us, evolution has kept it simple for the Christmas cactus. It can’t follow a calendar either. It turns out that most plants have evolved to flower either with long days and short nights – plants that bloom in summer and fall – or with short days and long nights – plants that bloom in winter and spring. Guess which one the Christmas cactus is – that’s right, long nights.

So, here is what to do:

• find a place in your house that is cool – definitely below 60 degrees, but not below 50.
• Move your Christmas cactus there, stop feeding and reduce the watering, so that the soil  becomes and stays almost completely dry.
• It doesn’t matter when exactly you do this – but it will change the time of flowering, since it takes time for buds to form and open.
• Try to do this in early fall if you want Christmas flowers.
• Keep it in the light for this time.
• Now, once it has settled in this new temperatures, every day for at least 10 days, you need to keep it completely dark – not even a flash of light.
• The easiest way is to put it inside a thick black garbage bag and close it tightly.
• If you do it at 6 pm, then you can open it no earlier than 10 am – you make adjustments to suit your daily schedule.
• 16 hours of dark, 8 hours of light for a couple of weeks. Now, bring it back into its normal home, at 70 degrees, and water and feed normally.

Watch, and you will start to see tiny red buds forming. Over the weeks they will expand and grow, until, wow!, you have blooms. That wasn’t so hard was it.

Remember, 16 hours of dark and drier soil for 2 weeks, at no more than 60 degrees. Blooms guaranteed.