Poinsettia
What would the holidays be without the iconic holiday plant: poinsettia. Here are some facts about poinsettias and how to care for during and after the holiday.
The poinsettia, Euphorbia pulcherrima, is a perennial shrub or small tree in its native range of Central America. Poinsettias were first brought to the United States from Mexico by US ambassador to Mexico, Joel Poinsett in the early 1800s. In the early 1900s, the plant was popularized and developed leading the way for the fantastic cultivars available today.
The brightly colored portion of poinsettias are actually not flowers, but modified leaves called bracts. The flowers of poinsettias are somewhat inconspicuous yellow flowers in clusters in the middle of the bracts. When selecting plants look for flowers buds that have just opened, not blackened or withered.
The bracts that make the poinsettia so beautiful are photoperiodic, sensitive to changes in daylength. As the days get shorter and daily dark period gets longer, poinsettias are triggered to start coloring the upper leaves (bracts) and producing flowers. A poinsettia takes about 8-10 weeks of short days/long night to initiate flowers and reach full coloration.
Figure 1 Poinsettia flower buds
Poinsettias have often been misrepresented as poisonous, and numerous studies have found that poinsettias are not poisonous to humans or animals. Of course, nor are poinsettias considered food, so curbing the desire to munch on this plant is reasonable to avoid stomach ache. All plants in the Euphorbiaceae plant family including poinsettia produce sap that contains latex. Those with a high sensitivity to latex may want to avoid getting the milky sap on skin.
A healthy poinsettia will remain attractive for many weeks, well after the holidays. Poinsettias like a bright or well-lit area, away from cold drafts with a temperature around 60-70F. Careful attention to watering is necessary because overwatering leads to root rot the most common problem in the home environment. Poinsettias should be watered when the soil is dry to the touch, the pot should also feel light when lifted. Most poinsettia come with a decorative pot cover, remove the pot cover when watering and allow the water to drain completely before replacing the pot cover.
Figure 2 Red and white poinsettia floral display
Once the poinsettia begins to look a little ragged, compost it or a poinsettia can be kept to rebloom the following season with a little work and the following care.
- From January thru March continue with general care same as above.
- March, cut plants back to about 4-8 inches of the soil. Separate into individual plants if needed and re-pot. Continue to grow in a bright inside location at 60-70F. Once new growth appears, start regularly using a fertilizer for flowering plants.
- Early June, acclimate the plant to the outdoors for a couple days. Once acclimated find a mostly sunny location for the summer. Early June is also a good time to re-pot. Pinch the plant once or twice between June and late July to develop a strong multi-stemmed plant, continue with regular watering and fertilizing.
- In early September return the plant to an indoor location with plenty of sun. In late September, the plant will need to start receiving a dark treatment of about 14 hours each night, for the next 8-10 weeks. It is important that the 14 hour dark period each night be uninterrupted for successful bract coloration. Continue to provide 6-8 hours of bright sunlight during the day, 60-70F temperatures and water as needed. Full coloration should be achieved in early December.
Not interested in keeping it alive for an entire year, simply compost when done. Visit a garden center, nursery or florist next year to purchase a fresh poinsettia and try something besides red.
Figure 3 Poinsettia trial showing diversity of cultivars and color
