Christmas Cactus

Check your light →

Near a window but shielded from direct rays, it sets the most buds. Farther back, where the light is softer, it still grows, just with fewer flowers come winter.

In the wild it perches on branches in the mountain forests of southeastern Brazil, 3,000-5,000 feet up, where conditions stay cool, shaded and humid (University of Wisconsin Extension; UC Master Gardeners). Indoors, an east-facing windowsill is usually ideal (RHS), and a few hours of morning sun suits it, though not much more (University of Wisconsin Extension).

In fall, darkness matters as much as light. Once nights reach 13 hours, around October, it needs each one unbroken to set buds (NC State; Pender County Extension). NC State lists lamplight in autumn among the things that can stop flowering, so a spare room or a sill nobody lights after sunset is worth the move.

Give it bright days, and let its nights stay truly dark.

About every 1-2 weeks in summer and every 10-14 days in winter, with the soil nearly dry between; once buds set, keep it evenly moist. A forest cactus, it drinks more than its desert cousins.

In the wild its roots sit in pockets of decaying leaves caught between tree branches, soaking up rainwater (NC State Extension). Indoors, NC State suggests an airy mix with peat moss, sand and perlite, and a pot that feels light when you lift it is a fair sign it’s ready (Pender County Extension).

From mid-September, ease off a little while the buds develop (NC State). Once they show at the stem tips, keep the routine steady: a hard dry spell, or a swing below 50°F or above 90°F, can make it drop buds before they open (Pender County Extension). The plant survives a lost season of buds; you’d just miss that year’s flowers.

Once buds appear, leave it where it is. Being moved, or parked by a radiator or a drafty door, is a common trigger for bud drop (NC State; University of Minnesota Extension).

Gone for a while? Two weeks is fine if it’s watered the day you leave, but not while it’s in bud: a dry spell then makes it drop them.

Chains of flat, scalloped segments rise and arch over the rim, about a foot tall and up to twice as wide. Give it a side table or wide sill; after it blooms, twist off a segment or two at the joint to keep it bushy.

Each segment runs about 2.5 inches long (NC State), and new ones grow from the tips of the last, the same place its flowers form.

Keep it a little snug in its pot heading into fall, when it sets buds; Pender County Extension notes it tends to bloom best pot-bound, so a container that looks slightly small is fine.

NC State calls its habit pendulous, and that weeping shape earns it a hanging basket or a tall plant stand by an east window, where the flowers hang down toward you.

The ASPCA lists it as non-toxic to dogs and cats, and NC State calls it safe for homes with pets or children. Its stems are smooth and spineless, too, so there’s nothing to prick small hands.

Among holiday gift plants, it’s one of the gentle ones: Penn State Extension files it on the nice side of the list. It’s considered non-toxic, with no serious trouble expected (Pet Poison Helpline). A pet that eats some may still vomit or have diarrhea for a while, and that usually passes within hours.

If your pet seems unwell afterward, or the upset doesn’t settle, call your vet or the ASPCA Animal Poison Control Center (a fee may apply).

If you have a cat that bats at anything dangling, a high shelf or a hanging basket keeps the flowers intact and the stems away from a curious mouth.

1. ASPCA: safe for dogs.
2. ASPCA: safe for cats.
3. CHOP: safe for kids.

Cats and dogs: The ASPCA lists it as non-⁠toxic.

Kids: CHOP and Poison Control list it as non-⁠poisonous.

Happiest at 70-80°F, and it shouldn’t sit below 50°F. It likes 50-60% humidity and gets by at 25%.

Temperature

70-80°F

Humidity

50-60%

Mealybugs and scale are the ones to watch for, and both settle on the flowers and stem segments. Red spider mites sit on the segments, and aphids can turn up anywhere. Look closely at each joint.

• Mealybugs
• Scale
• Red spider mites
• Aphids

Not many. Mealybugs, scale, spider mites, and fungus gnats turn up now and then, and root rot if the soil stays wet.

Mealybugs look like tufts of white cotton in the joints between segments; scale looks like small brown bumps, sometimes sticky. Wipe them off with a cotton swab dipped in rubbing alcohol (a fingernail lifts scale), then check again next week.

Spider mites leave fine webbing and pale speckles: rinse the plant in the shower, and if they come back, spray it with insecticidal soap. Fungus gnats are tiny flies hovering over soil that stays wet; let the top of the soil dry between soaks (7-10 days in most rooms) and they die off.

Root rot is the one to watch: stems go limp and shriveled even though the soil is wet, and segments start to drop. Let it dry out, empty the saucer, and water less often; if the roots are dark and mushy, start new plants from healthy segments (see Propagation).

Feed monthly from June to August at half strength. Pinch off tip segments under 1 cm at the end of September, then prune at the joints after flowering. Repot in late March every 2-5 years, one size up.

• Feed3× a year
• Pinch1× a year
• Rebloom routine1× a year
• Prune1× a year

A pot with a drainage hole, a little on the snug side, and a mix that drains fast: ordinary potting mix with a good share of perlite. In the wild it grows on trees, not in soil, so its roots need air.

Repot about every three years, in spring, just one pot size up; it blooms best a little pot-⁠bound.

Food helps it bloom: a houseplant fertilizer at half strength, once a month from spring through summer (UMN and Clemson Extension).

Flat green segments with scalloped edges link into chains that arch over the rim. The surface has a gentle gloss, and the stems pile up so densely that the pot’s soil disappears.