Poinsettias
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.
Watering
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.
Reblooming
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.
Flowering
Poinsettias 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.
Christmas
Cactus
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.
Watering
Although 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.
Lighting
These 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.
Fertilizer
Fertilize the plant every two weeks with a liquid houseplant fertilizer that
is high in potassium. When the flower buds are forming, do not fertilize.
Reblooming
The 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.
Repotting
Repotting can be done when the plant is finished flowering.
Propagation
The 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.
Christmas
Pepper and Jerusalem Cherry
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.
Florist's
Cyclamen
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 flowering
This 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 Flowering
After 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 Dormancy
Fertilize 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.
Kalanchoe
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.
Reblooming
After 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. Contact our office for information
on ordering copies of this bulletin.
January 1990
For more information contact: Tom Kowalsick, Extension Educator - Horticulture, CCE - Suffolk County
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