Christmas cactus will be in bloom soon, available at your local nursery and home and garden store, in many stunning colors to brighten our shorter days. Their bloom time can range from November to January, just when we could use that emotional lift the most.
Many people purchase these beautiful plants for themselves or receive them as gifts. They keep them during their bloom time to brighten their home, and then dispose of them once the bloom is gone. This time, this year, seriously consider caring for them during their off season. It will reward you this time next year with a bigger plant and no new purchase necessary.
Christmas cactus is the common term that nurseries use for any variety of Schlumbergera truncata or Schlumbergera x buckleyi. Plant breeders in their quest for more unique colors have created so many varieties of each that nurseries typically no longer provide the scientific names. One can tell the genetic lineage of their plant though by the shape of the stem segments.
S. truncata has a crab claw-like shape to its flat, fleshy stems which have ‘teeth' along the edges and at the tips of the branches. These are also known as Thanksgiving cacti because they bloom earlier than S. x buckleyi, the true Christmas cactus. S. x buckleyi stems are also flat and fleshy but with smooth scalloped edges.
While the lineage is interesting, the care and maintenance is the same for all varieties. The name ‘cactus' gives one the image of a plant that lives in desert sand; this is not that kind of plant. Its native origins are the tropical rainforests of Brazil, where it lives not in soil but in plant debris on other plants, where it would get its water and nutrients from the humidity around it. Due to its native habitat, one would think that caring for it here in our climate would be close to impossible, but not true!
In the home, these cacti require bright but filtered light near a south-facing window. They do best in 50–70 degrees F. During warmer months they can live on a sheltered patio. In order to mimic their native growing conditions, the potting soil should be loose and fast draining (for example, 40% perlite and 60% coconut coir). They like air around their roots, so it should dry out a bit between waterings. To induce bloom for the next holiday season, starting in mid-September, give it cool nighttime temperatures (50–55 degrees F), 12–14 hours of darkness, and reduce watering to compensate for slowed growth.
Schlumbergera species can be quite long lived. Given the right care they can brighten your living space for decades. Detailed care and reblooming instructions can be found at the link below in the UC publication titled Holiday Cacti. If you give one as a gift, include the publication below and hopefully the recipient will be able to enjoy it for years.
Help Desk of University of California Master Gardener Program of Contra Costa County (EDC)