Christmas Cactus 101
By Rob Sproule
What do the jungle covered mountains in southeastern Brazil have to do with Christmas? The small Schlumbergera genus clings to the damp rocks and moss filled trees of the humid, tropical forests there.
The Christmas cactus, which is actually a humid air and low light-loving succulent, has been a holiday staple for centuries. It’s been bouncing in and out of fashion since its discovery in 1815 (lately it’s back “in”). While it has nothing to do with Christmas except its blooming time, its longevity, ease of care, and translucent beauty keeps us coming back for more.
Think “jungle.” You’ll want to protect them from direct sunlight; give them distance from south or west windows. Have a mister bottle nearby daily to spritz their foliage: the more humid, the better.
If you’re a keener, fill their saucers with rocks and water. The pot sits on the rocks (not in the water), and the evaporating moisture increases the humidity: aim for %50-%60.
Don’t be in a hurry to repot them. Like many tropical plants, they thrive in a cramped, competitive environment. They’re used to having to fight for space, after all. Keep them root-bound in well-draining, sandy soil.
They aren’t gluttons, but fertilizing a few times a year with 20-20-20 will keep them strong. Stop feeding in late September.
They need more water than desert cacti. When the top inch of soil feels dry, water again. Water thoroughly to avoid salt build up.
How do you know they will always bloom at Christmas? Well, you don’t. In fact, with the other common names of Thanksgiving Cactus and Easter Cactus, you pretty much have a winter-long window when they might bloom.
You can help the timing by tinkering with the moisture and the light you’re giving them. Cut back on watering in early November. Only water when the first inch of soil is quite dry. Make sure they’re not too close to open windows that will freeze them with drafts.
Tuck them next to a window where they will get a few degrees cooler at night. Keep in mind that”¯they need plenty of darkness to set bud; at least 12 hours a night. Luckily for us, that’s not a problem.
If the flowers aren’t radiant in ideal time for Christmas, don’t sweat it. With everything else going on over the holidays, many people actually prefer that the flowers appear to brighten the bleakness of January.
Watering issues are the most common. If you’re giving too much water, you’ll start to see spots on the leaves or limp, generally weak stems.
Too little water is easier to deal with. The plants will wilt (that means you’ve pushed not watering too far), and drop their leaves and buds.
A red tinge on the leaves indicates too much light. It’s essentially a sunburn across the fleshy, succulent tissue. A little isn’t alarming, but tells you to move your plants out of direct light.
While generally pest free, Christmas Cacti can pick up opportunistic critters, generally from other plants. Spider Mites are most common; they are easily spotted when their tell-tale, fine webbing appears across the leaves.
Misting regularly helps prevent mites (they prefer dry foliage). If you already have them, a few shots of Insecticidal Soap, each about a week apart to match their life cycle, should stop them cold.
Mealy Bugs are rare but remain a threat. You’ll see gooey clumps of fairly disgusting white stuff in the nooks between leaves and stems if they turn up. They’re harder to get rid of than mites. Soak a cotton swab in rubbing alcohol and blot them one by one.