Christmas Cactus

11/27/2020 22:26

                                                                             By Julie Barnes

Christmas cacti are spectacular holiday plants brandishing lush pendulous flowers in an astonishing array of

 common Thanksgiving cactus, Schlumbergera truncata and the rare hybrid Christmas cactus,

Schlumbergera bridgesii, cross bred from the Thanksgiving cactus. The true Christmas cactus,

Schlumbergera bridgesii, blooms later and does not exhibit the same kaleidoscope of colors or variations

seen in the vigorous growing Thanksgiving cactus. These attributes make it less profitable for holiday plant

sales. For this reason the Thanksgiving cactus is sold as the “Christmas cactus.” If you want to possess a

true Christmas cactus you literally have to acquire this exceptional beauty from someone who has one

where its stem segments can be easily rooted. Otherwise it is not available in stores.

The name “cactus” brings to mind desert conditions and can be quite misleading to some. Besides desert

cacti, the cactus family also contains jungle cacti which grow in rainforests. These winter flowering

houseplants are native to Brazil’s moist rain forests resting on trees as epiphytes. An epiphyte grows on

another plant for support and does not take nourishment as a parasite would from a host plant.

Schlumbergera flourish in plant debris trapped among the tree branches maturing rapidly in the rainy

season. When the dry season returns they become dormant subsisting on water stored in their flattened

leaf like stem segments. These plants will deteriorate if treated like desert cacti. Schlumbergera thrive in

conditions similar to their native location: porous potting mix, high humidity, with partial shade in spring and

summer. They also bloom best when pot bound. Repotting should only be necessary every three years.

Thanksgiving and Christmas cactus differ mainly in the shape of their leaf like stem segments.

Thanksgiving cactus, Schlumbergera truncata, or Zygocactus, Claw or Crab cactus

blooms several weeks before the Christmas cactus. It has stem segments with

strongly toothed or pointed edges that make them appear claw-like. Its growth habit

seems to be more upright.

Christmas cactus, Sclumbergera ‘bridgesii’, blooms later

It has smaller smooth stem segments that are scalloped along

the edges. Its growth habit tends to more pendulous or drooping.

Schlumbergera are short day plants similar to poinsettias or mums forming buds as day length becomes

shorter than 12 hours. They also need a “chilling requirement” to initiate flower formation by subjecting them

to autumn temperatures below 550 F. To achieve this: Relocate the plant to a shady location outdoors in the

summer keeping the potting media consistently moist, then, in autumn only dampen the plant enough to

prevent it from wilting. Move it back indoors before temperatures drop below 450 F into a low light location

and withhold water in order to encourage re-blooming. After buds form and become quite noticeable, shift

the plant back into the light and water, preferably, in a sunny location with minimal temperature fluctuations

while allowing the soil to dry slightly before watering. If flower buds start to drop, overwatering, exposure to

cold drafts, being too close to a heat source such as a vent or fireplace, or low humidity can be the cause.

After it is done blooming, this plant should only be watered when the media becomes dry. Holiday cacti are

long lived plants that are often handed down from generation to generation. With proper care their dramatic

blooms can be a striking part of the holiday season.