Christmas Cactus
University of Arizona Pima County Cooperative Extension

This Holiday season you may acquire (through your own efforts or the generous intentions of others) a Schlumbergera bridgesii, otherwise known as a “Christmas Cactus.” This exotic beauty and prolific bloomer has been a holiday gifting tradition in Europe and the US for more than a century, since British botanists began breeding varieties for commercial sale in the 1860s. It is actually one of a few "Holiday cactus" that you can find at nurseries including Easter cactus and Thanksgiving cactus, all of which can be brought into seasonal bloom which roughly coincide with their namesake holidays.
Originally from the rainforests of coastal Brazil, the Christmas cactus is distinct from the cactus we know and love from our arid southwest landscapes. For starters, the Christmas cactus is an “epiphyte” which means that it is more at home growing in the crooks and on the branches of trees in its native rainforest range. It would be quite unhappy in our desert soils, but does great in a pot with rich but well-drained potting mix. In fact it even likes being a bit "cramped" in a pot and only needs to be potted up to a larger container once every 2-3 years. It can be fairly long-lived too with reports ranging from 40-100 years.
Their longevity can make them a great botanical heirloom too, gifted from one generation to another. To ensure that your Christmas cactus is in full bloom during the holiday season, you should take care to provide the appropriate temperature and the light conditions, and get started about 6-8 weeks before the holiday.
The Christmas cactus prefers cooler temps (60-65 degrees) and requires short days (longer periods of darkness; about 12-16 hours) to initiate blooming. If you have a cooler darker part of the house, you can relocate it there over night and then move it to a place of prominence for display during the day. Be sure to avoid drafty or ambient light (even your neighbor’s Christmas lights entering through a nearby window may be disruptive.
Keep the soil moist but do not saturate the soil or allow it to dry out between waterings. Watch for wrinkling or puckering along the flattened stems- which could indicate under or over watering. Abrupt changes in temperatures -due to cold/hot air coming from windows, fireplaces or heaters- can also cause the plant to drop its blossoms and flowers.
With some appreciation of this unique cactus’ origins and ecology your holidays will be a bit more tropical, colorful and festive, this year and- and perhaps many more!