The Christmas Cactus (Schlumbergera) is a popular houseplant recognized by its long, arching stems and vibrant, tubular winter flowers. Its unique appearance, featuring flattened, segmented stem sections, often causes confusion about its botanical classification. This tropical bloomer does not look like a typical spiny desert cactus, leading people to question if it shares the same drought-tolerant traits. The answer lies in the plant’s ability to store water within its modified structure.
Defining the Succulent Category
A plant is defined as a succulent primarily by its ability to store water in specialized, fleshy structures to survive periods of drought. These storage organs are typically thickened leaves, stems, or roots that allow the plant to retain moisture. All plants classified within the Cactaceae family, including the Christmas Cactus, are technically considered succulents due to this fundamental water-storage adaptation.
The Christmas Cactus (Schlumbergera × buckleyi) fits this definition because its flattened, leaf-like stem segments, known as cladodes, are fleshy and designed to retain water. These modified stems allow the plant to endure dry spells, though not to the same extreme as desert species. While many succulents are rosette-forming plants like Echeveria or spiky, arid-dwelling cacti, the Christmas Cactus is a succulent that evolved in a different, non-desert environment.
The Epiphytic Lifestyle of the Christmas Cactus
The Christmas Cactus looks different from its desert relatives due to its native habitat and lifestyle. Species in the Schlumbergera genus originate from the coastal mountains of southeastern Brazil, thriving in humid rainforests. They are classified as epiphytes, meaning they grow non-parasitically on the branches of other trees or in rock crevices, using the host plant only for support.
This jungle environment provides high humidity, filtered light, and a substrate of quick-draining organic matter. The plant anchors itself with aerial roots that absorb moisture and nutrients from the air and accumulating debris. This adaptation explains why the stems are flat and segmented, allowing them to capture sunlight in the dappled forest understory, rather than being thick and waxy to minimize water loss.
Specialized Care Compared to Desert Succulents
Since the Christmas Cactus is a tropical epiphyte, its care requirements differ significantly from desert succulents. Desert varieties prefer long periods of complete soil dryness between infrequent, deep waterings, but the Christmas Cactus needs more consistent moisture. Allowing the potting mix to dry out completely, a common practice for desert cacti, can cause the stem segments to shrivel and drop.
The soil composition must reflect its rainforest origins, requiring a mix rich in organic matter and highly porous, unlike the sand-heavy mixes used for desert plants. A slightly acidic, well-draining potting mix, often containing peat or bark, is preferred to mimic the decaying plant material found on tree branches. The Christmas Cactus needs bright, indirect light, as direct, intense sun exposure can scorch the stems, turning them red or pink.
How to Identify Other Holiday Cacti
The term “Christmas Cactus” often refers to any of the three popular “Holiday Cacti,” which are distinguished by the shape of their stem segments and their typical bloom time. The true Christmas Cactus (Schlumbergera × buckleyi) has smooth, rounded, or gently scalloped edges on its stem segments. It naturally blooms later, typically from mid-December through January.
The Thanksgiving Cactus (Schlumbergera truncata) is the variety most commonly sold, often mislabeled as the Christmas Cactus. This plant is recognizable by the distinct, pointed, or claw-like projections along the edges of its segments and typically blooms earlier, often beginning in November. The Easter Cactus (Rhipsalidopsis gaertneri) belongs to a different genus and features more rounded segments that generally bloom in the spring.