by Carol Siddall, Master Gardener
Being a gardener and loving the Christmas season, you can bet money I have a poinsettia in my home. I am known to give them as gifts also. They were the flowers for my December wedding, so they hold a special place in my life.
This plant was first introduced to the United States by Joel Poinsett, the U.S. ambassador to Mexico. Thus it was subsequently named the poinsettia. Back in the 60's most of the poinsettias grown and sold were still the tall red ones. They were hard for the florists to manage, so we started seeing shorter types coming into the market. Growing poinsettias became easier.
Today poinsettias are a major crop for greenhouse producers. They are available in just about every retail establishment you enter, and they are no longer just red in color. Several beautiful colors are available to chose from. You may be surprised to learn that the actual flower of this plant are the yellow blooms that form in the center of any poinsettia's colorful floral bracts. They are Euphorbias. Other members of this same family are the crown of thorns and the pencil plant.
According to Neil Sperry, a horticulturist living in McKinney, Texas, the plants are photoperiodic. That means they measure the length of the dark period (night) to determine when it is time to come into flower. Neil continues by saying a flower-inducing hormone is produced in their growing tips. That hormone is destroyed by light. When nights become long enough (around 14 hours of darkness), the plants come into flower.
The plants I bought this Christmas were an unrooted cutting in August. That is how rapidly they grow. Keep your poinsettia cool, bright and moist for the longest productive life inside your home. If leaves start to drop, moisture is needed. (you might mist them) Another cause of leaf dropping is a change in temperature. The goal is to keep the indoor temperature consistent.
If you try to save your plant for another season, start reducing the plant's exposure to sunlight in mid September to October. That means complete darkness for 14 hours. During the day, the plant should be in a sunny window where it can have bright light. How exciting it will be to see the magic unfold as the leaves start to turn colors in November! 12-28-2017