plant of the month
Poinsettia, Christmas star, Christmas flower, Mexican flameleaf, Mexican flame tree, Painted leaf, Lobster plant
Poinsettias are leafy plants, with dark green leaves topped with colored, modified leaf bracts, which many people incorrectly think are the flowers or flower petals. The real flowers are the tiny, mostly yellow berrylike cyathia in the center of each colored leaf bract. Some novelty varieties have crinkled, curved and/or twisted leaf bracts.
Natural hues include reds, burgundies and pinks; plum; red-orange; salmon/apricot/peach; creamy whites and ivories; pale yellows; and lime green, as well as a variety of marbled, spotted and striped bicolors. New varieties and colors are developed every year. Tinted and dyed poinsettias have gained favor with some consumers in recent years.
Poinsettias will last several weeks to several months, depending on variety, interior conditions, care and maturity of the plants at the time of purchase.
These holiday plants are generally available only in November and December although some hybridizers are experimenting with year-round varieties.
in-store and consumer care
Poinsettias need at least six hours of bright indirect (diffused) sunlight daily.
These plants require moderately moist soil at all times. Water them thoroughly, saturating the soil completely, when the soil surface is dry to the touch, then allow them to drain; do not allow pots to sit in water.
Average room temperatures (60 F to 70 F) are required—65 F to 70 F during the daytime and 60 F to 65 F at night. Cool conditions prolong bloom time. Never expose plants to temperatures above 70 F or below 50 F for extended periods.
Poinsettias thrive in humid air, so in dry interior environments, place pots on a pebble tray or mist leaves frequently. Keep plants away from the heat and dry air emitted by appliances, electronics, fireplaces and ventilating ducts.
At the retail and consumer levels, plant food usually is not necessary.
This differs from variety to variety. Exposure to the gas can cause epinasty (“drooping” leaves and bracts, and leaf-stem twisting); leaf drop; and cyathia drop.
These plants are susceptible to spider mites, mealybugs, whiteflies, greenflies and scale if displayed in an environment with air that is too dry.
Botrytis (gray mold) and root rot can occur with overwatering, too much misting, poor air circulation and/or display in too-cold environments.
Causes include too-low temperatures (lower than 50 F for extended periods), exposure to hot or cold drafts, not enough light, too-dry air, and/or overwatering or underwatering. Wrap poinsettias well when delivering in low temperatures.
WILTING, FOLLOWED BY LEAF YELLOWING AND LEAF DROP
The cause is either overwatering or underwatering.
EPINASTY (LEAF AND BRACT DROP)
The plant was exposed to ethylene gas, overwatered (root rot) and/or kept too long in a shipping sleeve (always remove sleeves as soon as plants arrive; the longer a plant remains sleeved, the more quickly its quality will deteriorate).
YELLOW OR BROWN LEAF EDGES
The usual reasons are too-dry air and/or too-high temperatures.
BRACT EDGE BURN
Too much fertilizer at the grower and Botrytis (gray mold) can cause this (see “Diseases,” ).
CYATHIA DROP, FADING BRACT COLOR
Causes include not enough light, too-high temperatures and/or too-dry air.
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Check that the cyathia (yellow-and-red berrylike flowers in the center of the colored bracts) are fully developed but unopened and displaying no pollen.
Look for plants with fully mature and thoroughly colored bracts (avoid plants with too much green around the bract edges); that are not bruised or blemished; that are not droopy; and that do not have “burned” or dried out edges.
Look for plants with plentiful dark green foliage all the way down the stems, and avoid plants with wilting, droopy, yellow and/or brown-edged leaves.
Check for waterlogged soil, particularly if the plant appears wilted; this could be a sign of irreversible root rot.
PESTS AND DISEASES
Examine plants carefully for signs of spider mites, mealybugs, whiteflies, greenflies, scale and Botrytis (gray mold).