Christmas Cactus
The Christmas Cactus is a popular holiday gift plant. But this plant is also the subject of frequent debate among gardeners with regards to care, maintenance and how to get them to rebloom.
Known as epiphytic cacti, they are native to tropical rain forests of the Americas. They are not parasites, but the derive nutrients from decaying plants.
"Epiphytic cacti have flattened, slightly succulent stems, sometimes incorrectly thought to be leaves. These stem consist of short segments and flowers are produced at the end of them." (Indoor Plants) A Christmas Cactus needs good, pourous soil and will do best in a sunny window away from hot drafts (like heat vents). Hot drafts cause the buds to drop. Try to find a window in a cooler room - the blossoms will hold longer.
Watering is another tricky subject with Christmas cacti. While in bloom, water the plant when the top inch of the soil is dry. Stick a finger into the soil up to the knuckle to test the soil. Don't overwater.
When the blossoms drop, the plant begins a resting period. During this time, keep the plant on the dry side, but water if the leaves begin to shrivel.
When new growth resumes, water more frequently.
What about care during the summer?
A Christmas Cactus will thrive outdoors, but be sure to place the plant in a shady or semi-shady spot. Then water as needed to keep the plant from shriveling.
The trick to getting the plant to blossom again is long nights (12 hours of darkness) and short days. "As they grow naturally in woodlands, epiphytic cacti need less sun than desert cacti, but being exposed to sunlight for part of the day helps to ensure good blooming. An east-facing window-sill is a good spot as it will capture the early morning sun, but will be in shade during the heat of the day." (Indoor Plants)
Exposing a Christmas Cactus to cool temperatures (50-55°F) will also encourage blossoming, so leave the plant outside as temperatures cool in the fall.
Bring the plant indoors gradually when temperatures get too cold, and keep in a cool, bright window. You will be rewarded with a lovely burst of flowers in time for the holidays.