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COLUMBIA, Mo. – With proper care, Christmas cactus is a gift that gives for many years, says University of Missouri Extension horticulturist David Trinklein.
Trinklein has recommendations for success with Christmas cactus:
Christmas cacti tolerate low light but perform best in bright, indirect light in the home. They benefit from brighter light during winter, but full summer sun can result in pale plants. If placed outside for the summer, keep plants in a semi-shady location. Christmas cacti prefer temperatures of 70-80 F for the April to September growing season.
Like most cacti, Christmas cacti tolerate underwatering better than overwatering, Trinklein said. Water only when the growing medium is dry to the touch. If you put a saucer under the pot to collect excess water, empty it to keep the water from wicking back into the pot. Failure to do so results in a soggy root environment, which is an open invitation to root rot.
Reduce watering from fall through spring. Only fertilize plants during their growth period of early spring through late summer. Use a regular fertilizer at one-quarter strength or a houseplant fertilizer according to label directions.
Keep Christmas cacti slightly pot-bound to induce prolific flowering. Repotting may be necessary every three years. Use a porous, well-drained potting mix. Commercial mixes made for epiphytes are good choices. Make regular peat-lite mixes into epiphytic mixes by adding perlite or sterile sharp sand to increase porosity.
Reblooming Christmas cacti can be challenging, Trinklein said. The cacti are short-day plants, but temperature affects their response to day length. In fact, flowering will occur regardless of day length under cool night conditions (50-55 F).
Prolific flowering happens when plants experience cool nights with at least 13 hours of darkness. Reducing water at this time to slightly stress the plant improves flowering. Expose Christmas cacti to short days, cool nights and dry conditions in mid-October for full bloom during the holiday season.
Sudden changes in temperature, light or other factors, such as excessive drying of the growing medium, can cause Christmas cacti to drop unopened flower buds. Poor flowering also happens when stray light interrupts the required long periods of darkness during short-day treatment. Interior lights, streetlights and even car lights can disrupt the required dark period and cause disappointing flowering, Trinklein said.
Christmas cactus is prone to root rot. Avoid overwatering and maintain strict sanitation. Remove common insect pests, which include mealybug and scale.
“Given proper care, Christmas cacti often outlive their caretaker and provide years of brilliant color around the holidays,” said Trinklein. “The small amount of effort required by these plants is well worth it when one considers the reward of seeing an ‘heirloom’ plant bloom year after year.”
Writer: Linda Geist
Published: Wednesday, Nov. 25, 2020