Poinsettia

Scientific Name: Euphorbia pulcherrima Willd. ex Klotzsch
Synonym: Poinsettia pulcherrima
Family: Euphorbiaceae

Recommended Temperature Zone:
Sunset®: 13, 26-27
USDA: 10

Frost Tolerance: Needs some protection on coldest nights.

Heat Tolerance: Questionable, needs afternoon shade and acid soil

Sun Exposure: Full sun to part shade

Origin: Mexico

Growth Habits: Evergreen or semi-deciduous shrub, up to 16 feet tall (5 m)

Flowers: Yellow or red flowers

Watering Needs: Moderate water, good drainage. Keep dryer when dormant.

Propagation: Cuttings

The name Poinsettia comes from Dr. Joel Roberts Poinsett, U.S. ambassador to Mexico from 1825 to 1829. Dr. Joel Roberts Poinsett was also a keen botanist and gardener. The poinsettia was used in Mexico to decorate churches at Christmas time and called flor de la noche buena, that is 'Holy Night Flower'.

Culture:
Poinsettia is the Christmas plant by excellence. After blooming, it will go dormant, lose its leaves. That's when most of the poinsettias find their way to the trash can. You can easily trim the branches to prevent legginess, and find a cool place to store it until early the last frost are gone (end of February in Phoenix), and either plant it in the ground or in a bigger pot.
Although the poinsettia enjoys full sun, in the hot deserts, afternoon shade will be helpful.
It needs slightly acid soil and a protected location. Fertilize every 2 weeks for best color.