Taylor Jamison
K-State Research, Extension
While the beautiful flowers of spring and summer may fade into memory as the colder months approach, many people look forward to the winter-blooming Christmas and Thanksgiving cactus.
Both plants are from the same genus of Schlumbergera cacti. Not sure which type of cacti you have? K-State horticulture expert Ward Upham explains the physical differences.
“Christmas cactus normally has smooth stem segments,” Upham said. “Thanksgiving cactus has hook-like appendages on each segment.”
Now a popular houseplant, Christmas and Thanksgiving cacti are native to the hot, humid jungles of South America. They are epiphytes, which means they grow on other plants for support and use nutrients from the environment around it – making them easy to care for and perfect to hang inside the house.
However, if your Christmas or Thanksgiving cactus is failing to bloom, Upham suggests ensuring it is meeting the proper requirements for temperature and light.
Common household temperatures are usually fine, but Upham advises never keep the plants below 50°F, as it will prevent flowering.
In addition, Christmas and Thanksgiving cacti usually require 25 consecutive nights for flower initiation. The nights must be greater than 12 hours long, which usually begins to happen around the Fall equinox – September 22nd, this year.
“A plant receiving natural sunlight but no artificial light during night hours will have this 25day requirement met about October 17th,” said Upham. “Alternatively, plants can be placed in a dark place, such as a closet, for more than 12 hours each day to induce flowering.”
During the day, Christmas and Thanksgiving cacti prefer bright, indirect light. Too much sun, however, may cause leaves to turn yellow. If this happens, move the plants further away from the window or light source.
Other conditions that Christmas and Thanksgiving cacti prefer is constantly moist soil – but not waterlogged – and kept a little pot-bound.
After all the requirements are met, wait an additional 9-10 weeks for the flowers to complete development and provide lovely blooms for the holiday season.
Upham and his colleagues in K-State’s Department of Horticulture and Natural Resources produce a weekly Horticulture Newsletter with tips for maintaining home landscapes. The newsletter is available to view online or can be delivered by email each week.
Interested persons can also send their garden- and yard-related questions to Upham at wupham@ksu.edu, or contact your local K-State Research and Extension office.