The poinsettia, Euphorbia pulcherrima, a popular potted plant at Christmas time, provides effective color in the home decor during and after the holiday season. The newer poinsettia cultivars are long-lasting in contrast to the cultivars available a few years ago.
The true flowers of poinsettias are inconspicuous parts in the centers of the colorful bract clusters. Depending on variety, the bracts are red, pink, cream, or white.
When purchased, poinsettias should be in prime condition for decorative use in the home, office, etc. They should be well-shaped plants exhibiting dark green foliage with bracts free from defects.
The soil in which poinsettias grow should be kept moist at all times, but not excessively wet. Apply water when the soil surface begins to feel dry and apply enough to the surface until it runs out of the drainage hole. For best results, never allow the foliage to wilt between applications of water.
Avoid placing poinsettias in areas where air movement from windows, doors, fans, or radiators exists. Placement in such areas will cause rapid water loss from the foliage and bracts resulting in the inability of the roots to absorb a sufficient amount of water to offset wilting, thus causing premature flower, bract, and leaf drop.
Poinsettias are among the most difficult plants to rebloom in the home. After plants begin to drop their leaves, withhold water to encourage dormancy, and store in a cool location (50-60 degrees F). Following the last frost in the spring, move the plants outdoors to full sunlight. Prune two or three inches from the end of each stem. The plants will develop a large amount of new growth during summer.
It is probably best to start cuttings from the original plant, which would then develop into sizes you are normally inclined to purchase at Christmas.
In July or August remove three- or four-inch cuttings from the new growth on the plant. Insert each cutting in a small pot containing a sterilized mixture of half sand and half peat moss. Keep the cuttings shaded and watered during the rooting period (about three weeks). Then set the plants in larger pots in a sterilized mixture of equal parts of soil or sand, peat moss, and perlite.
Locate the plants in full sunlight, and provide a temperature range of 60-70 degrees F at night. Keep the soil moist, and apply a fertilizer solution (one tablespoon of 20-20-20 per gallon of water) each week.
If you decide that you want to allow your original plant to grow larger and eventually get it to rebloom instead of taking cuttings and starting new plants then follow all of the above procedures, except the paragraph on taking cuttings in July or August.
FloweringPoinsettias form flower buds when the days are shorter than 12 hours. Beginning the first of October, protect the plants from light by placing them in a dark closet between 5:00 PM and 8:00 AM daily. Exposure to even the slightest amount of artificial light during this period will inhibit flowering. After 40 days of this treatment, the plants can be kept in normally lighted rooms. With water, fertilizer, and 60-70 degree F night temperatures, the plants will flower during December.
The Christmas cactus, Schlumbergera bridgesii, is a popular plant at Christmas time, which sports intricate flowers in red, salmon, white, and pink. They are one of the few holiday plants suited to growing all year long (no dormant period required). If the plant receives proper care, it is very long- lived.
WateringAlthough this plant is a cactus, it requires more water than other cacti. Keep the soil of this plant evenly moist all of the time. Do not overwater the plant because waterlogged roots can cause the flower buds to drop. Underwatering or excessive dryness can bring on the same thing. In late summer or early fall, when the buds are forming, water only enough to keep the stems from wrinkling or shriveling. After the buds are formed, you can resume normal watering.
LightingThese plants like a bright location and some sun. However, strong summer sun may cause the plant to turn yellow.
Note: Christmas cacti are sensitive to light. If you move the plant, be careful not to change its position relative to the source of light. This can weaken the small, newly-formed buds, and they may fall off.
FertilizerFertilize the plant every two weeks with a liquid houseplant fertilizer that is high in potassium. When the flower buds are forming, do not fertilize.
RebloomingThe flowering of a Christmas cactus is related to the length of the day and the night temperature. If the plant is kept outside during the summer, the cool temperatures of early fall nights (50-55 degrees F) are usually enough for the plant to set buds. This will probably take place before you bring the plant indoors (before the night temperature goes below 50 degrees F or before the first frost). The buds will form regardless of the amount of darkness they receive. If the plant is grown indoors all year around, then it will need artificial short days or about 13 hours of darkness to initiate bud development. You can do this by placing the plant in an unused room or closet from 6:00 PM to 7:00 AM or draping it with a dark cloth for this period. If the plant is small enough, a brown paper bag may work, too. After the buds form, it can be treated normally, and you can watch the buds develop.
RepottingRepotting can be done when the plant is finished flowering.
PropagationThe Christmas cactus can be propagated from a cutting taken from the tip of the stem. "Y"-shaped cuttings are best, though others will also root. Each cutting should consist of two or three jointed segments. The cuttings should be inserted into a small pot of potting soil. Keep moist.
The Christmas pepper, Capsicum annuum, and the Jerusalem cherry, Solanum pseudocapsicum, have brightly colored fruits. Keep the plants in full sunlight and keep the soil moist. Cool temperatures will help prolong the life of the fruits.
After the fruits drop, discard the plants. New growth is ungainly, and they will not flower again.
The fruit is poisonous if eaten - Keep out of the reach of children and pets.
The florist's cyclamen, Cyclamen persicum, is sometimes seen during the Christmas holidays. These plants are distinguished for their compact foliage and abundant bloom. The flowers, borne at a level above the leaves, are white or shades and tints of red. The plants are difficult to maintain in most homes.
Care during flower bud development and floweringThis period usually starts in mid-September if you have saved a plant from last season. It is also the care for a plant purchased in bloom during the holiday season. Cyclamen requires a night temperature of 50 degrees F, and day temperatures of 60 to 65 degrees F in full sunlight. The leaves turn yellow quickly and flower buds die if the temperature is too high or light intensity too low. Inadequate moisture also produces adverse effects.
Dormancy After FloweringAfter flowering, withhold water to induce dormancy, and store the pot in a cool location until the following June. Repot the corm in a sterilized soil mixture of one part peat moss, one part soil, and two parts coarse sand. Leave the upper half of the corm exposed to prevent rotting.
Care After DormancyFertilize twice a month with a water-soluble fertilizer, such as 5-10-5, 15-30-15, or other 1:2:1 ratio fertilizer for houseplants. Keep the plant in indirect bright light until mid-September, then expose it to full sunlight at low temperatures for mid-winter flowering.
The common kalanchoe available during the Christmas season is Kalanchoe blossfeldiana. These plants are small, compact, and bear red, orange, and yellow flowers in clusters above the foliage. The plants are usually available throughout the winter. For extended bloom, they require cool temperatures, full sunlight, and constantly moist soil.
RebloomingAfter flowering, the plants can be retained for their foliage if they receive direct sunlight; ungainly new growth develops if they receive too little light. Rebloom is unreliable without controlled daylength. For Christmas bloom, put the plants in complete darkness from 6:00 PM until 7:00 AM for 30 days, beginning September 1. After this treatment, plants will develop buds under normal conditions.
Information for this publication obtained from: The Selection, Care, and Use of Plants in the Home, by Charles C. Fischer and Raymond T. Fox, Information Bulletin #117, a Cornell Cooperative Extension Bulletin.