As we mentally arrange and rearrange our house, we spot that beautiful Christmas cactus that we just could not resist in November. The plant is still in its prime, with its bright green leaves shaped like crab claws and its funnel-like bright flowers still lovely to behold.

 

The name Christmas cactus does not reflect what this plant is about. Often the label identifies it as Zygocactus, which is not correct. The true Christmas cactus (Schlumbergera bridgesii) blooms around Christmas; its sister, the crab cactus (Schlumbergia truncata), blooms about a month earlier.

 

The difference between the two is relatively small. The Christmas cactus has smaller, more scalloped leaves that tend to droop slightly. Both are botanically classified as epiphytes.

 

Common orchids are probably the best known epiphytes. These plants grow on other objects or plants and get their water from the moist air around them instead of from the soil.

 

The Christmas cacti are from the South American rain forests, where they grow mostly in trees under the main canopy. They root amongst plant debris in tree branches or on the ground in stony areas. They can grow as tall as four feet and just as wide. In their native habitat, they receive as much as 17 inches of rain in the growing season, but only three inches in the dry season. Most of the Christmas cacti in California stores are grown in Half Moon Bay.

 

Although many sources will tell you that Christmas cacti should be considered houseplants outside of Hawaii, they seem to be happy on the Napa Valley floor, as long as they reside on a protected porch or deck with diffused light. They are healthiest at temperatures between 50?F and 70?F and may drop their flowers in hot, dry weather. They will not survive frost. Bring the plant indoors or cover it with a cloth to keep it from freezing. Those living in the hills surrounding Napa Valley should consider it an indoor plant in the winter.

 

The Christmas cactus is not demanding if planted in loose, well-draining soil. A slightly acidic mix of 40 percent perlite and 60 percent peat moss is ideal. In summer, provide extra humidity by misting or putting the plants in a tray with pebbles and water This extra effort will keep flower and leaf drop to a minimum.

 

The plant requires water when the soil is dry, but don’t let it dry out. As it grows and blooms, it will require more water. Keep fertilization to a minimum. A solution of 10-10-5 fertilizer applied every two to four weeks during March to September, its growing season, is sufficient. Repotting the cactus every two to three years will allow it to grow larger.

 

It is a simple process to induce the cactus to bloom in time for Christmas. In mid September, put the plant in a cool place (50?F to 55?F), such as a closet or spare room, where it can be in the dark for at least 12 to 14 hours per day. Cut back on the watering. As the blooms start to appear, increase the water and move the plant to a slightly warmer room (60?F to 65?F). Keep away it from heat or air conditioner vents and bright sunlight.

 

After bloom, the cactus may be moved to a permanent site outdoors once nighttime temperatures climb above 40?F.

 

Around Napa one can find many old Christmas cacti on covered porches and stoops. These ancient specimens have been sitting there in the same spot for years, blooming from as early as November through as late as February every year. My own crab cactus also blooms around Valentine’s Day or Mother’s Day, depending on the weather, as well as sporadically through the summer. Christmas cacti are easy plants that can brighten the holidays for generations, given minimum attention from their owners.