Look at the edges of the flat stem segments. A Thanksgiving cactus has 2 to 4 pointed teeth along each edge; a Christmas cactus has rounded edges, per Clemson HGIC. The Easter cactus, a third holiday cactus, has smoother segments with bristles at the tips and blooms in spring, per Iowa State Extension.
Side-by-side comparison
| Feature | Thanksgiving cactus | Christmas cactus | Easter cactus |
|---|---|---|---|
| Accepted name (POWO) | Schlumbergera truncata | Schlumbergera × buckleyi, an artificial hybrid (POWO) | Rhipsalidopsis gaertneri (POWO) |
| Stem segment edges | 2 to 4 upward-pointing teeth (Iowa State) | Scalloped, without pointed teeth (Iowa State) | Smoother, with 4 to 6 slight ripples and brownish bristles at the tips (Iowa State) |
| Flower form | Erect and tubular; does not hang down (NC State) | Tubular, slightly zygomorphic, droops down (NC State) | Star-shaped, 1.5 to 3 inches across (NC State) |
| Anther color | Yellow (Clemson) | Purplish-brown (Clemson) | Not given by these sources |
| Flower colors | White to red, lavender and salmon-orange (Iowa State) | Rosy-red, about 3 inches (Iowa State); magenta red to pink (NC State) | Pink or red (Iowa State) |
| Typical bloom | Mid-November to late December (Iowa State) | Late November to early February (Iowa State) | March to May, may rebloom in early fall (Iowa State) |
| Bloom trigger | Blooms after about 6 weeks of short days; cool nights also required (UMN) | Blooms after about 6 weeks of short days; cool nights also required (UMN) | Sets buds after 8 to 12 weeks (UMN); long nights, then a cooler spell (Iowa State) |
How to tell them apart
Start with the stem segments, which are there whether or not the plant is in bloom. Clemson HGIC says each Thanksgiving cactus segment has "2 to 4 saw-toothed serrations or projections along the margins," and that Christmas cactus margins are "more rounded." NC State describes Christmas cactus stems as "segmented with rounded marginal notches." Iowa State describes Easter cactus segments as smoother than the other two, with 4 to 6 slight ripples and brownish bristles at the tips.
Flower position separates the two Schlumbergera in bloom. NC State says Thanksgiving cactus blooms "are erect, tubular, and do not hang down like the flowers on Schlumbergera x buckleyi," and its Christmas cactus page says those flowers "droop down." Easter cactus flowers are different again: NC State calls them "star-shaped, funnelform-campanulate."
Anther color is a close-up check. Clemson HGIC says: "The anthers of the Thanksgiving cactus are yellow, whereas the anthers on the Christmas cactus are purplish-brown."
Bloom timing helps, with overlap. Clemson says Thanksgiving cacti normally flower "approximately a month before Christmas cacti bloom." The windows Iowa State gives overlap from late November through late December, so timing alone won't settle it for a plant in bloom in December. Easter cactus blooms primarily from March to May.
Why plants sold as Christmas cactus are often Thanksgiving cacti
Iowa State Extension says: "Most plants sold as “Christmas cactus” are actually Thanksgiving cactus or hybrids." NC State says "Most of the plants sold in stores today are the sterile hybrids (S. x buckleyi)" of S. russelliana and S. truncata, the species it calls Christmas cactus and Thanksgiving cactus. NC State also lists "False Christmas Cactus" among the common names of S. truncata. Neither page says why the trade sells them this way, so check the stem segments rather than the label.
The correct botanical names
- Thanksgiving cactus: Schlumbergera truncata (Haw.) Moran is accepted by Kew POWO, native to Brazil Southeast. POWO lists Epiphyllum truncatum and Zygocactus truncatus among its synonyms.
- Christmas cactus: POWO lists Schlumbergera × buckleyi (T.Moore) Tjaden as "an artificial hybrid" with the formula "S. russelliana × S. truncata" (POWO). POWO gives no native range for it. Iowa State says it has also been known as Epiphyllum buckleyi, E. rollissonii and Schlumbergera bridgesii, and UMN Extension still uses S. bridgesii. POWO treats the name Schlumbergera bridgesii as a synonym of S. russelliana, one of the hybrid's parents.
- Easter cactus: POWO accepts Rhipsalidopsis gaertneri (Regel) Linding., native to Brazil South, and lists Hatiora gaertneri and Schlumbergera gaertneri as synonyms. Clemson uses Hatiora gaertneri, and Iowa State and UMN use Schlumbergera gaertneri, so the same plant appears under all three names in extension references.
Does care differ?
Not for everyday care. Clemson HGIC gives one set of light, water, soil and fertilizer instructions for Thanksgiving and Christmas cacti together, and UMN Extension and Iowa State give one set for holiday cacti as a group. The difference is how to bring on flowers. Thanksgiving and Christmas cacti bloom after about 6 weeks of short days, and cool nights are also required, per UMN. For Easter cactus, Iowa State describes a fall sequence of 14 to 16 hours of darkness at 60 to 70°F for 3 to 4 weeks, followed by 47 to 55°F for 4 to 6 weeks.
For full care, including how to time blooms, see the Thanksgiving cactus care guide and Christmas cactus care.
Are they toxic to pets?
The ASPCA's Toxic and Non-Toxic Plants database has a Christmas Cactus entry. It gives the scientific name Schlumbergera bridgesii, lists Easter Cactus as an additional common name, and classifies the plant as non-toxic to dogs, cats and horses. There is no entry under Thanksgiving Cactus or Easter Cactus, and the entry does not name S. truncata, S. × buckleyi or Rhipsalidopsis gaertneri. A separate Shrimp Cactus entry names Schlumbergera russelliana, one parent of the Christmas cactus hybrid, and lists it as non-toxic to dogs, cats and horses. NC State's Plant Toolbox pages for S. truncata, S. × buckleyi and R. gaertneri each tag the plant "non-toxic for cats" and "non-toxic for dogs."
The ASPCA's plant list adds that "the consumption of any plant material may cause vomiting and gastrointestinal upset for dogs and cats." If a pet ate part of a plant and you are worried, call your veterinarian or the ASPCA Animal Poison Control Center at (888) 426-4435.
Frequently asked
Sources: Kew POWO — Schlumbergera truncata, Kew POWO — Schlumbergera × buckleyi, Kew POWO — Rhipsalidopsis gaertneri, Kew POWO — Schlumbergera bridgesii, Clemson HGIC — Thanksgiving & Christmas Cacti, Iowa State Extension — All About Holiday Cacti, UMN Extension — Holiday cacti, NC State — Schlumbergera truncata, NC State — Schlumbergera × buckleyi, NC State — Rhipsalidopsis gaertneri, ASPCA — Christmas Cactus, ASPCA — Toxic and Non-Toxic Plants, ASPCA Animal Poison Control, ASPCA: Shrimp Cactus