OLATHE, Kan. - Picking the best poinsettia comes down to knowing how to judge the plant's maturity and health.
"You want it to last as long as possible, but you also want it to peak at just the right time," said Alan Stevens, horticulturist with K-State Research and Extension.
The best way to judge a poinsettia's maturity is to examine its flowers, Stevens said.
That can be tricky unless shoppers know that the colorful parts on top of each stem are not flowers. They may look like petals, but they're actually bracts -- leaves that change color. Poinsettias are a native of Mexico, and their bracts' color switch happens as the days grow shorter, the nights get longer and they prepare to bloom.
"These special leaves' purpose is to attract insects to pollinate the flower, which starts out as a cluster of ball-like structures in the middle of each set of bracts," Stevens said. "When those ball-like buds are still tight, the plant has some maturing to do. So, it might be an appropriate choice to buy in late November."
A few opening buds mean the plant should reach full flower in several weeks, he added. So, it could be a good choice when shopping for Christmas decor in early to mid-December.
"By the 25th, the colorful reproductive structures should be exposed, and they'll even have a dusting of yellow pollen. The plant will be at its peak, its most colorful and interesting," Stevens said. "After the flowers fade and drop, the plant will still be attractive. But you'll be more likely to put it with your houseplants than to feature it on the dinner table."
Plant height can have little or nothing to do with plant health, he said. Traditionally, breeders try to ensure blooming plant height will be about 2.5 times the width of the pot, so plant and pot look in proportion. They also grow what they think will sell best - which tend to be poinsettias in the 15- to 18-inch range (both wide and tall).
But, healthy, shorter poinsettias also are available, Stevens said. And, one of the newer types on sale now is much, much larger. It's a dramatic tree form, encouraged by hand to develop a single 1- to 5-feet-tall "trunk" with a large, round poinsettia head.
Whatever their height, however, quality poinsettias are dense -- lush-looking, he said. For example, one in a 6-inch pot should have at least five sets of bracts.
Healthy poinsettias have sturdy stems. They show no signs of disease, damage or insect infestation (typically, tiny whiteflies or aphids). They're neither drooping nor wilting. And, they have dark green foliage down to the soil line - no yellow intruders and few to no lost leaves.
How they're displayed can be a clue to the kind of care poinsettias are getting, Stevens said. And that, in turn, can be another sign of whether they'll last very long.
Nurseries typically ship the plants in a plastic or paper wrap, to prevent damage. If temperatures are below 50 degrees, poinsettias will also need the protection of a wrap for the trip from store to warmed car to warmer home. Even a few minutes in frigid temperatures can damage the plants' leaves.
While poinsettias are on the shelf, however, they should be wrap-free, the horticulturist said. Wrapping may be a basic for protecting poinsettias, but it also makes the plants deteriorate more quickly. So, the less wrapped time, the better.
Displayed poinsettias need to have enough room, as well. Cramming poinsettias together on a shelf is like asking for bent and broken plant parts, he said.
"I always tip the plant out of the pot and check its root ball, too. White roots are healthy. Brown roots aren't," Stevens said. "At the same time, I check the moisture level of the soil. It should be moist, but not wet. And, a poinsettia sitting in dry soil will deteriorate quickly."
All of those checks are fairly easy to do - which is a good thing, he said. Plant breeders are coming up with so many new "looks" that choosing which variety to buy can be difficult.
Red bracts remain buyers' favorite. But, pink, white and maroon also have fans. Plus, the newer varieties are likely to have several bract colors, due to speckles, marbling or variegations. The color combos can range from looking quite formal to being cheerfully random. Some new varieties also have bracts that are scalloped, twisted or curved, including the increasingly popular Christmas rose and winter rose poinsettias.
Recently, a poinsettia with variegated leaves entered the market. Also, retailers are offering spray-painted poinsettias. (So far, blue seems to be the favorite.) Some plants even come with a dusting of glitter.
Stevens keeps up with the market because he's in charge of the floral field and greenhouse trials at Kansas State University's Horticulture Research and Extension Center near Olathe.
K-State Research and Extension is a short name for the Kansas State University Agricultural Experiment Station and Cooperative Extension Service, a program designed to generate and distribute useful knowledge for the well-being of Kansans. Supported by county, state, federal and private funds, the program has county Extension offices, experiment fields, area Extension offices and research centers statewide. Its headquarters is on the K-State campus in Manhattan.