Outdoors - Dont throw out that holiday plant - Don’t throw out that holiday plant

    If you received or purchased a Christmas cactus or poinsettia at the holidays there is no need to throw them out after they finish blooming. With a little bit of attention and care you can get them to bloom again next season.  

    The Christmas cactus (Schlumbergera bridgesii) is a popular houseplant, especially when we can get it to bloom in the holiday season. In spite of its name the plant does not bloom by the calendar, but rather in response to short days and cool nights. In its native habitat the combination of these two results in abundant blooms in December—but when we use it as a houseplant in our climate we must “manipulate” its environment in order to ensure blooms near the holidays.

    The Christmas cactus is not a desert plant, rather it is native to humid tropical rain forests; consequently it is important that moisture and humidity are controlled. They are epiphytes, which means they cling to or are supported by trees in the forest, but they are not parasitic, feeding off of the host plant. Bromeliads and orchids are other examples of epiphytes.

    For best practices resulting in good blooms for the holidays, treat your plant as having three distinct growth periods. The first is the vegetative growth period, which occurs first in January and then throughout the summer months. During these periods the plant should be watered generously. It can be placed outside after the last frost in May. It should receive adequate sunlight during the summer and be fertilized lightly every three to four weeks. Ideally, leave the plant outdoors in a bright location, until the night temperatures drop to 55°to 65° F and the daytime temperatures raise only 5-10° higher. Bring the plant indoors before the first frost.

    The rest period will begin in the fall, once you have brought the plant indoors. Isolate the plant in subdued sunlight for about a month. This also ensures that any insects brought in on the plant do not migrate to other plants. Water moderately during this period. There is a common misconception that because the plant is a cactus, letting it dry out during this rest period will force it to bloom. This is not the case. After about a month place the plant in a sunny window.

    The bloom period should begin in about 6 weeks if the night temperatures are less than 55° F.   If the night temperatures are between 60-65°, the plant will require at least 12 hours of total darkness each night in order to bloom. If night temperatures are nearer to 70° the plant may not bloom at all. Once the plant begins to bloom increase the water and keep it in full sunlight. The plant is very sensitive during the bloom period. Any changes in water, humidity, temperature or even the direction of the sunlight may result in bud drop.

    The cactus should be planted in standard cactus soil mix and it is not necessary to repot until it becomes top heavy. As long as there is ample sunlight and relatively cool night temperatures the cactus should reward you with ample blossoms, season after season.

    Poinsettias are what are referred to as photoperiod plants. This means that they set buds and produce flowers as the days shorten and there are less hours of direct sunlight. If you want your poinsettia to flower again you must provide a minimum of 14 hours of total darkness for 6-8 weeks beginning around the first of October. The best way to ensure this is to put the plant in a closet at night—one that you know will not be opened for at least 14 hours since even the slightest amount of stray artificial light will slow or stop the re-flowering process. The night temperatures should be between 60º and 70º so make sure the closet does not get too cold at night. And be sure to take your plant out of the closet each day! It requires 6-8 hours of bright sunlight each day, which can be difficult around the holidays. If you are diligent about practicing this routine you should be rewarded with poinsettia flowers surrounded by brightly colored bracts by next Christmas. 

Happy New Year

    Note:  There are two other holiday cacti, the Thanksgiving Cactus (Schlumbergera truncata) and the Easter Cactus (Rhipsalidopsis gaertneri). If your cactus consistently blooms at the “wrong” time, it is possible that you have one of these varieties