Check the flowers when choosing a poinsettia

Poinsettias come in many colors and forms. New selections appear every year. Choose a plant with uniformly dark green foliage. However, cultivars with lighter colored or mottled bracts typically have lighter green foliage. Plants with pale green, yellow or fallen leaves generally have a root disease problem, have been overwatered, had an excessive dry period, or received limited fertilization. Bracts should be well developed with little pollen showing on the flowers.
Poinsettias do well in the home and keep their color until mid-March. The showy red, pink, white, yellow, bicolored or speckled modified "leaves" are called bracts. With proper light and temperature, they accumulate the anthocyanin pigments that give them their color. The flowers (botanically called cyathia) of the poinsettia are in the center of the bracts. Male and female parts are present, along with a yellow-edged nectary with sweet, fragrant nectar. Make sure that flowers are present and healthy for a longer display in your home.

When outside temperatures approach 35 degrees F, be sure the plant is well wrapped or sleeved before transporting. Low temperatures, even for short periods, can damage leaves and bracts. Remove sleeves promptly to prevent epinasty, a downward bending of the petioles, which are the slender stalks that attach the bracts to the stem.