by Sara Williams
Saskatchewan Perennial Society
Christmas cactus, Thanksgiving cactus and Easter cactus have added joy to our homes for over two centuries, since they were brought back from Brazil in the early 1800s. They are long lived, relatively inexpensive and easy to care for. Here’s how!
Light: They grow best in light shade or bright indirect sunlight. Direct sunlight can burn the leaves, giving the stems a pink to reddish tinge. During the fall, the Thanksgiving and Christmas cacti require shorter daylengths (8 to 10 hours) and cooler temperatures to set flower buds.
If placed indoors near a west- or south-facing window, make sure the light is filtered through a sheer curtain or hang them high enough so that they only receive indirect light.
Water: Holiday cacti are tolerant of dry, slightly under-watered conditions during the spring and summer. Following bud set in the fall, the growing medium is best kept more evenly moist to prevent flower bud drop.
Water plants thoroughly about once a week, allowing excess water to run out through the drainage holes. Never let them sit in water or allow the soil to become waterlogged, especially during winter. Nor let the soil completely dry out either.
Temperature: They do best with daytime temperatures of 65 to 70 °F (18-21 °C), and evening temperatures of 55 to 65 °F (13-18 °C). Ideal spring and summer growth from April to September occurs at temperatures between 70 to 80 °F (21-27 °C). This sounds complicated, but if your home is 70 °F (21 °C) during the day and slightly lower at night, and the plants are near windows, they’ll do fine.
Place them away from warm, dry drafts coming from heat vents, fireplaces or other sources of hot air which can cause the flower buds to drop.
Fertilizer: Fertilize plants monthly, using a complete, soluble fertilizer with trace elements, such as 20-10-20 or 20-20-20, applied at half the recommended rate.
Growing Media: The soil should be well-drained with good aeration. They do not grow well in heavy, wet potting mixes.
Repotting: They don’t need re-potting often and actually bloom better when “pot bound.” Use terra cotta or clay pots which are porous and tend to wick water away. Ensure they have drainage holes.
Choose a pot that’s only a bit larger (e.g. an inch or two [2.5-5.0 cm] wider pot). Repot once every three years, when they look ragged or when roots begin to grow out of the drainage holes. This is best done after flowering in late winter or spring.
Summer holidays? Holiday cactus can be set outdoors in the summer in a shady location protected from the wind. Bring them in once the temperature drops below 50°F (10 °C).
Pruning: Remove one or two stem segments from each branch immediately after blooming. This forces the plant to branch out, developing additional stems (and flowers).
Propagation: Take cuttings of 3 to 5 stem segments in May or June, allowing the cut ends to dry out for a few days. Use well-drained potting soil and clean containers for rooting. Place the cuttings about one inch (2.5 cm) deep. Water the soil well and cover with clear plastic. Keep the soil evenly moist but not overly wet. Place them in bright, indirect light until roots have formed, generally after three to eight weeks. Remove the plastic and apply a very dilute fertilizer solution when watering. Wait about eight to ten weeks before repotting in permanent pots. New leaf or stem growth usually indicates that roots have formed. Temperatures above 70 °F (21 °C) and up to 81 °F (27 °C) in long day/short night conditions speed rooting.
How to get a holiday cactus to bloom
In my experience, holiday cacti are not nearly as fussy in terms of daylength and temperature as a lot of books and articles would lead one to believe – maybe because the plants haven’t read those articles? Or more likely, modern breeding has developed a more flexible response to daylength and temperature for flower bud initiation.
For about six weeks prior to blooming, they require 12-14 hours of dark to set buds. This corresponds to the naturally shorter days of fall.
Once flower buds form, do not move the pot until flowering is finished. Unopened flower buds can drop if there is a sudden change in temperature, light or insufficient water.
Blooming starts when the daylength is approximately equal to the night length (12 hours each) and when the temperature is between 50 to 60° F (13-16 °C).
Mine are hanging fairly high in north- and west-facing windows where they are shaded from direct sunlight. Indoor lights are turned on randomly from morning to night and have not disrupted the initiation of flower buds or flowering.
Sara Williams is the author and coauthor of many books including Creating the Prairie Xeriscape, Gardening Naturally with Hugh Skinner and, with Bob Bors, the recently published Growing Fruit in Northern Gardens. She continues to give workshops on a wide range of gardening topics throughout the prairies.
This column is provided courtesy of the Saskatchewan Perennial Society (SPS; firstname.lastname@example.org ). Check our website (www.saskperennial.ca) or Facebook page (www.facebook.com/saskperennial) for a list of upcoming gardening events.