So how can you be sure that your Christmas cactus from past years will also be blooming beautifully this Christmas? If you have attempted to research the answer to this question, you undoubtedly came away more confused than ever. Even within all the various bodies of plant experts, there appears to be conflicting information. Some claim that the Christmas cactus must be provided with long hours of uninterrupted darkness (12-15 hours) each night like the poinsettia. Others assert that a night temperature of 50-60F is the key that induces blooming. To confuse matters more, many experts say the Christmas cactus requires BOTH long hours of darkness and cool temperatures to stimulate blooming. While some claim one method or the other and some say both, the Horticulture department at Purdue University states that either treatment will trigger blooming but both are not necessary.  In this case, 12 hours of nightly darkness should be started about mid-October and continued for 6-8 weeks or until the buds are well formed. When opting for the cool temperature treatment, start by early November. When buds are fully formed, they should be moved to warmer temperatures (65-75F) for flowers to open. Whichever method you choose, the Christmas cactus should get strong light during the day.

 

Still confused and not sure which method to follow for best results? Let us look at the native habitat for Christmas cacti which is mainly the rainforests of Brazil. In October and November (when the Christmas cactus would be forming flower buds), night temperatures are around 50-65F. The length of daylight during this time is 12-13 hours. Common sense would dictate that the Christmas cactus would benefit the most by both darkness and temperature control. 

 

From personal experience, my Christmas cacti bloomed every year by way of temperature control. I did not intentionally provide long, dark nights. However, as I lived where winters were severe, the Christmas cactus was strictly a houseplant. I was of the notion that they required cool nights to bloom.  My Christmas cacti occupied the guest bedroom for two months where it was kept about 55-60F, received sun during the day, and was in the dark by 5:00pm because of our short days at that time of year. They did receive both darkness and cool temperature treatment and bloomed prolifically.  

 

The other thing to consider when setting your expectations for Christmastime blooming is whether you actually have a Christmas cactus (Schlumbergera x buckleyi), Thanksgiving cactus (Schlumbergera truncata), or Easter cactus (Rhipsalis gaertneri). The Thanksgiving cactus blooms in November and is often sold as a “Christmas Cactus” or “Holiday Cactus”.   All three holiday cacti also have other acceptable botanical names through reclassification over the years. However, they each have distinct characteristics to enable positive identification. The Christmas cactus flowers hang downward and the stem segments have several rounded (not pointed) indentations on the margins. The Thanksgiving cactus flowers bend outward where connected to the stem causing the flowers to display horizontally and the stem segments have several definite points in the margins.  The Easter cactus flowers are very different having a more open look with distinct petals and the stem segments have smooth edges with very few, if any, indentations in the margins. 

 

Christmas Cacti are easy to care for. Here are some other tips to keep your Christmas (and Thanksgiving) cactus healthy during bud set and blooming time:        

 

Note the horizontal blossoms and points on stem segments compared to the Christmas cactus at the top which has rounded lobes and the blossom hangs downward.

 

 

 

Photo credits: 

Christmas Cactus by Judg57 on photobucket.com

Thanksgiving Cactus by Skomor on photobucket.com