— By Nan Sterman
Poinsettia season is upon us! Growers ship out the bright red and soft yellow colored plants every day, sending them to nurseries and garden centers across the country.
A rainbow of poinsettias await being shipped to gardens, nurseries, and resorts across California
Thanks to late Encinitan Paul Ecke Jr., poinsettias are the plants we mostly closely associate with the holiday season. You might be surprised to learn, however, that poinsettias originated in the semi-arid regions of Mexico. They are tough plants that can go from house to garden with surprising ease.
Poinsettias offer an amazing variation in flower size, shape, and color, including this speckled poinsettia grown by Armstrong Growers.
The botanical name for poinsettias is Euphorbia pulcherrima. The Euphorbia family includes many common garden plants and many succulents such as crown of thorns (Euphorbia milii). Collectively, the plants in this genus are called “spurges.”
In their native Mexico, in-ground poinsettias grow to large shrubs, even small trees, ten or twelve feet tall and wide. What we think of as poinsettia flowers are really brightly colored bracts. The actual flowers are tiny yellow structures in the very center of the bracts. It’s those bracts, that make the plants so attractive. They are also what breeders tinker with to create different colors and patterns.
Growing poinsettias indoors can be a little tricky. Ironically, they most often die from overwatering. Water infrequently and let the soil surface dry out between waterings. Drainage is important so remove the fancy foil wrapper as soon as you get the plant in your house. If you place a plate or bowl beneath the pot to catch excess water, prop up the pot on gravel or pot feet so the poinsettia sits above the water.
To keep your poinsettia going indoors, place it in bright light where temperatures stay in the mid 60’s.
Once the holidays are over, don’t throw your poinsettia away – plant it in the garden. Along California’s south coast, plant just after the new year. Inland, plant until early April, or until there is no danger of frost. Plant into well draining soils. Just like container grown poinsettias, in-ground poinsettias die if kept too wet.
Daytime light isn’t nearly as important as night light management for these fall/winter bloomers. Poinsettias bloom only if they have total nighttime darkness from September to December. Total nighttime darkness means no light from a nearby window or streetlight or house light. None. Interestingly, this characteristic was one key to Ecke’s success. In a greenhouse, he could easily emulate long, dark nights.
Breeders constantly work on developing new varieties of poinsettias, new colors, new sizes, new flower shapes.
Poinsettias go into a state of suspended animation when nighttime temperatures fall below 60 degrees, so after you plant, don’t expect to see any growth until spring. In fact, it’s common for poinsettias to go into transplant shock and temporarily drop all their leaves shortly after planting.
Once that new spring growth begins, and daytime temperatures exceed 60 degrees F, fertilize monthly with a general-purpose organic fertilizer. Follow the directions on the package.
If you like big, rangy poinsettias, don’t bother pruning. But if you prefer more compact, bushier plants, prune according to the holidays. Prune the branches back by up to half on Memorial Day. Prune again on the 4th of July and again on Labor Day. Shape the plant as you prune. New flower buds start to form after Labor Day, so stop pruning or you will cut off the buds.
