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.
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 DROOP)
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 reason for this problem is 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” in this section).
CYATHIA DROP, FADING BRACT COLOR
Causes include not enough light, too-high temperatures and/or too-dry air.
To view 31 additional Poinsettia varieties, please download the PDF.
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||WHAT’S IN A NAME The common name “poinsettia” was given in honor of Joel Robert Poinsett (1775-1851), a gardener, botanist and diplomat from South Carolina, who was the first U.S. ambassador to Mexico, from 1825 to 1829; he sent these plants from Taxco, Mexico, to Charleston in 1828, where he began propagating them and sending them to friends and botanical gardens.
The genus name Euphorbia was given in honor of Euphorbus, a Greek physician who lived during the end of the first century B.C.
The specific epithet (species name) “pulcherrima” means very handsome/pretty.
FAMILY Euphorbia is a member of the Euphorbiaceae (spurge) family. Relatives include croton (Codiaeum), chenille plant (Acalypha) and cassava/tapioca (Manihot).
HOME SWEET HOME Poinsettias are native to the tropical southern half of Mexico.
OLD WIVES' TALE Contrary to widely circulated misinformation, poinsettias are not poisonous to humans or other animals—unless ingested in enormous quantities, and then only mild discomfort would be experienced.
U.S. PRODUCTION Commercial production of poinsettias began in Southern California in about 1909, when the Ecke family grew them as cut flowers. sfr
||poinsettia buying tips
FLOWERS 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.
COLORED BRACTS 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
• without “burned” or dried out edges.
LEAVES 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.
SOIL 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 insects and Botrytis (gray mold).
||getting poinsettias to rebloom
Getting poinsettias to rebloom can be a challenge and is a bit of a process, but it can be done. Here are the steps to follow.
LATE MARCH OR EARLY APRIL Cut plants back to about 8 inches in height. Continue regular watering, and fertilize with an all-purpose fertilizer. By the end of May, you should see vigorous new growth.
AFTER ALL CHANCE OF FROST HAS PASSED Place plants outdoors when night temperatures will no longer drop below 55 F. Continue regular watering, and fertilize every two to three weeks.
AROUND JUNE 1 You may transplant plants into larger pots—no more than 4 inches larger (in diameter) than the original pots. A soil mix with organic matter, such as peat moss or leaf mold, is recommended. In milder climates, you may transplant plants into a well-prepared garden bed that is rich in organic material and has good drainage.
LATE JUNE, JULY OR AUGUST Pruning may be required during the summer to keep plants bushy and compact. Pruning must be done prior to Sept. 1. Make sure plants receive indirect sunlight, and water them regularly.
OCTOBER, NOVEMBER AND DECEMBER For eight to 10 weeks, starting Oct. 1, plants must be kept in complete darkness for 14 continuous hours each day/night, followed by six to eight hours of bright sunlight daily. To achieve the required darkness, move the plants to a totally dark room, or cover them with large boxes. Plants also require nighttime temperatures between 60 F and 70 F.
Important: Stray light of any kind and/or temperatures below 60 F or above 70 F can delay or entirely halt the reflowering process.
Continue watering and fertilizing regularly. Carefully following this routine should result in a colorful display of blooms for the holiday season.
Some information provided by:
Botanica, by R.G. Turner Jr. and Ernie Wasson
Chain of Life Network® , www.chainoflife.org
Complete Guide to Conservatory Plants, The
by Ann Bonar
Complete Houseplant Survival Manual, The
by Barbara Pleasant
Dictionary of Plant Names, by Allen J. Coombes
Ecke Ranch; www.ecke.com
Hortus Third, by Liberty Hyde Bailey and Ethel Zoe Bailey
Houseplant Encyclopedia, The
by Ingrid Jantra and Ursula Krüger
New House Plant Expert, The, by Dr. D.G. Hessayon
SAF Flower & Plant Care
by Terril A Nell, Ph.D. and Michael S. Reid, Ph.D.
Stearn’s Dictionary of Plant Names for Gardeners
by William T. Stearn