Christmas or Thanksgiving Cactus
I have had them for as long as I can remember, most of them gifts from friends who gave me a start. Although we call all of them Christmas cactus, there are two different plants.
Thanksgiving cactus (Schlumbergera truncata) is what is currently sold as Christmas cactus because buyers preferred getting plants that bloom earlier than the end of December. Thanksgiving cactus have pointed, tooth-like notches on the margins of the green stems. Thanksgiving cactus bloom around Thanksgiving but that’s in part because of the amount of light exposure and temperature you give them. I will get back to that in a minute.
Christmas cacti (Schlumbergera bridgesii) have rounded notches on the margins of the stem segments. They look like someone came along and cut off the little stem-edged horns. If you have an older cactus or inherited one, those are more likely to be the old-fashioned Christmas cactus, no longer available on the US commercial market. This plant has been known to grow for 75 years or more so they do become almost like family members.
In their native Brazil, schlumbergera grow among tree branches in shady, humid rain forests. Our fall and winter are their summer so to get them to bloom when we want them to, regulating their light exposure or temperature is key to simulating their native conditions.
If you want them blooming in December, limit the amount of light they get starting mid-September. They need 13 hours of daily darkness to set buds. Cover them with a dark cloth or put them in a closet every night to simulate those conditions.
If you don’t want to fuss with denying them light, expose the plant to temperatures between 55 and 60 degrees for six weeks until you start seeing flower buds forming. Stop fertilizing and reduce watering. You are simulating a Brazilian winter. A cold basement works well.
Once flower buds set, return the plant to normal light conditions and resume watering. When in bloom, these plants should be watered about once a week or when the top half of the soil in the container becomes dry. Lack of water will cause the flower buds to drop. Buds will also drop because of excessive heat, too much light, cold drafts, sudden change in light and temperature and inadequate watering. Yep, they can be a little touchy.
To make sure you are not over-watering, insert a finger into the plant soil up to a first knuckle to determine if the soil is moist enough. Over-watering is a common issue with these plants.
After flowers fade, stop watering for about 6 weeks. This will allow the plant to rest.
If you want to get your plants to be bushier, give them a June haircut. Snip off the top two or three stem segments of each stem to encourage the plant to grow more stems. The trim will promote flower development where the stems have been cut.
Don’t throw out those cuttings, you can root them in soil and get new plants started.
Charlotte Ekker Wiggins is a certified gardener, beekeeper and sometimes cook. Copyright 2016 used with permission, all rights reserved. This material may not be published, broadcast, rewritten or redistributed. Contact Charlotte at firstname.lastname@example.org.
THANKSGIVING CACTUS – Thanksgiving cactus have little horn-like edges to their stems. This Thanksgiving cactus is in a hanging basket in my basement and tends to set buds by mid-November because the basement stays cool.
THERE WILL BE A QUIZ – Which one is this, Christmas cactus or Thanksgiving cactus? Notice the smooth edges on the stems, this is a Christmas cactus from a start a friend gave me several years ago. (Photos by Charlotte Ekker Wiggins).