This week’s plant is the Christmas cactus. The plants we think of when we hear Christmas cacti are actually three different species of cacti, the Christmas cactus, Thanksgiving cactus, and Easter cactus, known collectively as holiday cacti. Holiday cacti are native to the forests of South America and were brought to Spain by returning explorers more than 300 years ago.
In their native habitat the holiday cacti are epiphytes, like air plants. While they grow on trees they are not parasitic; they draw their nutrients from decaying organic matter that they find on the tree instead of the tree itself. Interestingly Holiday cacti do not have true leaves. What we think of as their leaves are actually stem segments called cladodes.
A true Christmas cactus (Schumbergera bridgesii) typically blooms from late December to March. Their leaves do not have quite the pointy projections that the Thanksgiving cactus does, but are not as rounded as the Easter cactus. Their flowers are a red-ish color.
The Thanksgiving cactus (Schlumbergera truncata) is what people are typically referring to when they are speaking about a Christmas cactus. It is the most widely grown species. Its blooms can be a range of colors (from white to red to lavender to orange and many shades in between) and typically appear from late November to late December. The Thanksgiving cactus has distinct projections from the side of its stem. The picture at the top of this page is a Thanksgiving cactus, as that is the species I have in my apartment.
In an entirely different genus than the Christmas cactus and the Thanksgiving cactus is the Easter cactus (Rhipsalidopsis gaertnerii). The Easter cactus typically blooms from March through May and has pink or red flowers. It has been known to bloom again in fall. The Easter cactus has rounded scalloped edges to its stem segments in contrast to the Christmas and Thanksgiving cacti.
Fortunately all holiday cacti have similar growing conditions. The only difference among them is the amount of light required to set flowers. They are typically very easy to care for and can live for a very long time, up to several decades. The following requirements apply to all the holiday cacti.
Size: Holiday cacti branches can grow up to 3 ft (91 cm) long if not pruned. The flowers measure 1-3 in (2.5- 7.5 cm) in length.
Water Requirements: Holiday cacti are happiest when their soil is kept evenly moist. Being from a tropical environment, they are not as tolerant of drought as other cacti.
Light Requirements: The holiday cacti prefer light shade. Light that is too intense can burn the plants.
Soil Requirements: The Holiday cacti like well–drained soil.
Temperature Requirements: Holiday cacti do not like temperature extremes or drafty locations. They prefer temperatures between 55-75°F (12-24°C).
Nutrient Requirements: It is recommended to fertilize with a high-potassium fertilizer once every 2 weeks after flower buds form. Otherwise a typical houseplant fertilizer is fine.
Pruning: A good time to prune your cacti is after it is done blooming. This will encourage the plant to branch. The cuttings can then be used to start new holiday cacti. Directions here.
Pests: Holiday cacti have few disease or insect problems. They can occasionally develop root rot or be plagued by mealy bugs or spider mites.
How to make them bloom:
Both the Thanksgiving and Christmas cacti are short-day plants, requiring a shorter day-length and cool temperatures in order to set flowers. They require at least 12 hours of uninterrupted darkness . According to the Iowa State Handout :
“To ensure that the plants bloom around Thanksgiving or Christmas, place them in a spare bedroom or basement where no artificial lights are used at night. The plants should receive bright light during the day and the temperature should be kept cool, under 65°F.”
Easter cacti are day-neutral plants and will bloom with the amount of light normally available at that time of year.
Once you see flower buds on any holiday cacti, make sure to protect them from drafts and keep the soil moist to prevent those buds from falling off.
San Diego Natural History Museum – General information about the Christmas cactus and its history.
Reiman Gardens @ Iowa State University Growing Holiday Cacti Handout – Discusses the different types of holiday cacti and how to care for them.
Purdue Extension Christmas Cactus FAQs – General Care instructions for Christmas Cacti.
Organic Gardening Tips for Christmas Cactus Care – Growing guide and care instructions
Clemson Cooperative Extension – Detailed information about Thanksgiving and Christmas Cacti.
University of Connecticut Home and Garden Education Center – Detailed information about Holiday Cacti.