Holiday cacti: Christmas cactus, Thanksgiving cactus, and Easter cactus
Thanksgiving cactus (Schlumbergera truncata), Christmas cactus (Schlumbergera bridgesii), and Easter cactus (Rhipsalidopsis gaertneri syn. Hatiora gaertneri) are popular houseplants and often given as gifts during the holiday season. They can also be very long-lived. It's common to hear of these plants being passed on from generation to generation and sometimes living over 100 years! Although true cacti, these plants are native to rain forests and epiphytic meaning they grow on other plants and derive moisture and nutrients from air and rain. The need for high humidity, bright but filtered light, and soil kept relatively moist most of the year sets these plants apart from the majority of cacti and succulents.
Easter cactus (R. gaertneri) flower.
As houseplants, holiday cacti are grown for their beautiful, exotic flowers. However, people often complain about lack of flowers. Therefore, it's important to understand how light, temperature, and overall plant health affects blooming. Though called Thanksgiving, Christmas and Easter cactus, these common names are primarily for marketing purposes and provide only a general reference for the time of year these plants may bloom.
Holiday cacti are called "short day plants" meaning in order to produce flower buds; they require shorter days (fewer hours of light) and/or cool night temperatures. One way to initiate buds is by leaving plants outdoors in a protected location until just before frost danger. The shorter days and cooler nights signal the plant to produce buds resulting in abundant blooms.
Before bringing plants indoors in the fall, examine holiday cacti for overall health and signs of pests.
- Identify, remove and treat for pests as necessary. If using a pesticide, make sure the plant is listed on the label, read and follow all label instructions, and store/dispose of the container properly.
- Prune off diseased, broken or dead branches.
- Remove debris such as leaves from the soil surface.
- Check that all the container drains freely, and wipe the outside of the container with a damp cloth to remove insect eggs, bits of soil, cobwebs, etc.
Locate holiday cacti indoors a cool, bright location where daytime temperatures are 65-70° F and evening temperatures are 55-65° F. If plants are exposed to cooler night temperatures of 55° F, plants will bloom in approximately 5-6 weeks, sometimes regardless of the day length. However, if the night temperature is 60-65° F, these plants must have at least 12 hours of complete darkness every night for about 6 weeks in order to bloom. Plants are unlikely to bloom if exposed to night temperatures above 65° F. Note: Easter cactus (Rhipsalidopsis gaertneri) may take 8-12 weeks to flower after exposure to cool nights (55-65° F) and short days.
During the summer, plants may be located outside on a deck, patio, window box, etc. in part shade (3-6 hours of sunlight per day). Filtered sunlight, such as under a tree, is preferable as it mimics the plant's natural habitat. Excessive sunlight may result in pale green branches, drought, and sunburn.
Holiday cacti require good drainage and aeration for healthy root growth. Place plants in a sink to drain when watering and remove any excess water from saucers and decorative pots. Allow soil to dry out between watering. Note that plants will not grow well in heavy, wet soils and excess water may result in dropping flower buds, wilting and ultimately root rot. Do not allow plants to sit in excess water after rainfall or supplemental watering. If water has been abundant (e.g heavy rainfall) and plants appear wilted, they may be suffering from too much water. Allow the plants to dry out, check the container for adequate drainage and re-locate the plant to a drier, part shade site. Holiday cacti bloom best when kept somewhat pot-bound, so healthy plants may only need repotting about every three years.
Recommended potting mix for holiday cacti:
- 1 part sterile potting soil
- 2 parts peat moss
- 1 part sharp/builder's sand or perlite
Once flower buds have started to develop, holiday cacti do not like to be disturbed. Plants may drop buds due to drafts or sudden changes in temperature or humidity levels. Even the direction and amount of sunlight they receive can result in dropping buds. If the plants are to be displayed in a warmer room than the one in which the buds were initiated, move them there as soon as the buds appear. As long as there is adequate light and a relatively cool night temperature, the flower buds should continue to develop normally and will reward you with spectacular blossoms.
After plants have finished blooming, water less frequently, increasing again in spring or early summer when the plants resume more active growth. Fertilize monthly June - August with a balanced houseplant fertilizer at half-strength. In the fall when flower buds are forming, change to a fertilizer with low nitrogen (N), and high phosphorus (P) and potassium (K) formulation such as 0-15-10 (0% nitrogen, 15% phosphorous and 10% potassium).
After flowering, plants can be pruned to encourage branching. Use a small sharp pruner or knife to cut plants where two cladophylls (branch sections) join. The plant will produce 1-2 new cladophylls where it was cut and increase its branching. New plants may be propagated from the cuttings. Dip the base of the cutting in water and then rooting hormone (found at garden centers). Place the cutting in damp builder's sand or potting media that drains well. Place in bright light with temperatures of 70-80° F to promote good growth, and keep the media moist, but not wet. After 2 weeks, use a small spatula or popsicle stick to gently lift the cutting and check for new roots. Once roots have formed, plant the cuttings in cactus soil, water and place in a bright window.
|Plant doesn't bloom.||Indoor temperature is too warm.||Lower room temperature to 55-65°F at night, 60-65°F during the day.|
|Plant needs short days and long nights in a 24 hour time period.||Put plant in total darkness for a minimum of 12 hours. Place in bright light for the remainder of each 24 hour period.|
|Plant lacks nutrients.||Apply half-strength fertilizer with low N and high P and K in the fall.|
|Plant drops flower buds.||Changes in temperature||Locate plant away from drafts and heaters/vents.|
|Excessive number of buds for plant to support.||Plant is self-pruning. Maintain good care - proper watering, fertilize at half-strength, bright light and cool temperatures - to keep plant healthy.|
|Plant looks wilted even though soil is wet.||Too much water causing roots to rot.||Allow plant to dry out. Make sure container and potting media drain freely, and plant does not sit in water.|
|Plant drops branches.||Plant is very large and can't support the weight of the branches.||Prune back some of the larger branches. Re-pot into a slightly larger pot.|
|Plant is brown and "corky" at base.||Normal plant aging.||Confirm this is not scale. Otherwise, no action is required.|
|Black, wet, slimy lesions that start at soil line, progress upward to top of cladophyll; branches drop off; plant wilts, collapses, often dies||Bacterial soft rot caused by Erwinia spp.||Destroy infected plants. Prevent by keeping watering to a minimum, and water at base of plant to avoid splashing bacterium from soil onto plant.|
|Foliage turns gray-green, wilts, stems rot at the soil line, plant collapses, branches drop off. Roots are dark and mushy.||Root and stem rot caused by fungi Pythium and Phytophthora spp.||Purchase healthy plants. Avoid overwatering. Make sure pots and soil media drain well.|
|Blackened, circular sunken lesions. Black spores on lesions fuzzy in appearance.||Drechslera cladophyll rot (also called Helminthosporium cladophyll rot) caused by fungus Drechslera cactivora.||Destroy infected plants. Prevent by keeping watering to a minimum, and water at base of plant to avoid splashing fungal spores from soil onto plant. Rhipsalidopsis is very susceptible, Schlumbergera is moderately susceptible.|
|Cladophylls and roots die; Tan lesions, infection at border of cladophyll.||Fusarium cladophyll rot (Fusarium oxysporum).||Destroy infected plants. Prevent by keeping watering to a minimum, and water at base of plant to avoid splashing fungal spores from soil onto plant.|
|Small flying insects that look like fruit flies.||Fungus gnats which thrive in plant soil that is continuously wet.||Avoid overwatering plants. Allow soil to dry out between watering. Remove plant from soil, wash off roots and re-pot in a clean container with fresh, sterile potting soil. Trap larvae with slice of raw potato placed on top of soil; discard regularly to remove larvae.|
Klingman, G., Easter Cactus: Plant of the Week, University of Arkansas Extension Ornamentals Extension News. Accessed 15 December 2015.
Poole, R.T. et. al Holiday Cactus Production Guide. Accessed 14 December 2015. IFAS Central Florida Research and Education Center, University of Florida.