Holiday Cactus
If your Christmas cactuses have finished blooming don’t throw them away. Christmas cactuses can become long-lived house plants that will bloom year after year. Move them next to a sunny window or place them on your porch or patio throughout the summer and into fall.
Christmas cactus is known by the scientific name Schlumbergera bridgesi. Thanksgiving cactus is a related species. Its scientific name is Zygocactus truncatus or Schlumbergera truncatus. Thanksgiving cactus blooms from October to November and has flat, glossy green leaves that are distinguished by two prominent teeth (claws) at the growing tip. Flowers are usually scarlet. Christmas cactus is distinguished from the Thanksgiving cactus by its rounded leaves with blunt tips. Flowers are red with a purple tinge in the center.
Another holiday cactus that blooms later on in the spring is the Easter cactus. It blooms in March and April and is scientifically classified as either Schlumbergera gaertneri or Rhipsalidopsis gaertneri. Easter cactus has long, flattened joints, dull green leaves with rounded margins and a few bristles at the growing tips. Flowers are a deep scarlet and star-shaped. Also, they are symmetrical, which distinguishes them from the other two holiday cacti. There are many new hybrids which share some of the same characteristics but offer more variety of colors and larger flowers.
Holiday cacti are known for their colorful tubular flowers and ease of care. They include Christmas, Thanksgiving and Easter cacti. Christmas cacti have flattened leaves with rounded teeth on the margins as opposed to the Thanksgiving cactus that has pointed teeth. Easter cacti have pointed teeth with fibrous hairs in the leaf joints. Under normal conditions the holiday cacti will bloom close to the holiday suggested in its name. Florists will often force plants into bloom at other times. Most of the Christmas cactus sold are actually Thanksgiving cactus and will bloom in subsequent years at Thanksgiving time.
Holiday cacti live in the rain forest of Brazil. As epiphytes they live in tree branches happily rooted in accumulated organic debris with rainfall amounts varying from 17 inches per month in December through March to just 3 inches per month in the subsequent dry season.
A common concern is the holiday cactus no longer blooms. Holiday cacti are short day plants meaning they bloom when nights are over 12 hours long and daylight periods are between 8-10 hours for 6 weeks. Streetlights or indoor lighting may disrupt the required dark period so they may need to be covered each night. Holiday cacti will also flower if exposed to prolonged cool temperatures between 50-55 degrees F. No flowers will form at night temperatures above 68 degrees F regardless of light length.
Holiday cacti can be placed in a shady spot in the garden in summer or in an unheated porch until temperatures get below 50 degrees. The naturally longer nights and cool temperatures in late summer will encourage flower development. I placed my plant in a closed dark closet to initiate blooming but a spare bedroom or garage where temperatures were cool and no lights were used at night works also.
Once plants are in flower, they should be kept in bright, indirect light. Day temperatures of 70 degrees F and evening temperatures of 60-65 degrees F are considered ideal. Bring plants indoors if temperatures fall below 40 degrees F. Be sure to water thoroughly, but let plant dry slightly between watering. It is important not to let soil dry too much during flowering. These plants prefer to be pot bound. For best results only repot when unstable to the next slightly larger pot.
Once flowers fade, continue to grow the plant as a houseplant. Soil should be well drained and most container soils will work. Fertilize monthly between April and October with a complete houseplant fertilizer. Prune plants in June to encourage branching and more flowers. Just remove a few sections of each stem with your fingers or a sharp knife. The removed pieces can be rooted in moist vermiculite to make more plants.
Christmas cacti sometimes drop unopened flower buds, which may be caused by low humidity, a sudden change in temperature or light, or soil that is too dry. The most common insect pests are mealybugs and soft brown scale. The major disease is stem and root rot. Plants appear wilted and dull gray-green with water-soaked dead areas near the soil line often with faded reddish margins. Stem leaves often fall off. Avoiding excessive watering to prevent. Cut out infected areas, repot into clean soil.
submitted by Karen Blackburn