Poinsettia plants are native to Mexico where they grow wild and tall and are often planted as colorful perennial hedges. Here on the Eastern Shore, the poinsettia is most often purchased as a winter holiday plant for its colorful bracts that blaze bright red, clear white, soft pink, creamy pink & white marble, soft blends of color and the bright mix of red with white splashes.
Many think that the colorful bracts are the flowers, but they are truly modified leaves to assist the pollinators to find the tiny yellow flowers that grow in the center of each rosette of colorful bracts.
Many poinsettias are used as annuals, colorful beauty to brighten up the indoors when the weather outside is frigid. Once the holidays are over, the plants are tossed away or composted.
Some poinsettias do survive the winter months indoors due to the care their owners took to keep them healthy. To be successful in keeping poinsettias alive is not difficult; they prefer to grow in brightly sun lit rooms with room temperatures staying between 60 and 75 degrees. Try to place the poinsettia out of the way of drafts from doors, heating vents and away from cold windows.
Most poinsettias sold come in decorative pot covers, but once the plants arrive in a home those pot covers should be removed.
The poinsettias can be placed into a decorative pot after putting a few pebbles or marbles in the bottom to allow good drainage.
Poinsettias hate wet soils! It is good to remember that plants native to Mexico are used to warm temperatures and dry soils, so they thrive when watered only once a week with the soil allowed to dry out in the top 1-2 inches of potting media between watering. Once garden soils warm up, the poinsettias can be placed outside in the full sun.
They can create a lovely tropical touch when planted in the sunny gardens, or planted into larger containers to allow them to grow larger over the summer. Some garden enthusiasts love to keep the poinsettias alive all winter with the plan of having them bloom for the next winter. This is not difficult and can be a fun project for garden lovers of all ages. First, repot the plants with new potting media in a container that is at least 1 or 2 inches larger than the original container in early spring.
In May, trim back the plants so they are 3-4 inches above the soil line. Keep the plants in a lightly shaded area to recover and grow new foliage for a few weeks, then move the plants to where they can receive morning sun. After a week or so, move the poinsettias to a full sun location. When the new foliage is about 1-2 inches long, begin to water with a diluted amount of 20-10-20 plant fertilizer once a month. Once the new growth stretches to 4-5 inches, lightly pinch the growing tips of each branch. This will allow the plant to grow new branches and create a larger plant with a lot more leaves. The tips of the branches can be pinched each time the branches grow 2-3 inches longer until the first of September. Around the first of September spray the tops and bottoms of all the leaves with an insecticidal soap to clean the plants before bringing them indoors. Place the plants in a room that has bright sunny windows to continue to grow. This is where the tricky part begins! The plants need at least 14 hours of total darkness to begin to develop the colorful bracts, but they also need at least 10 hours of full sunlight to grow their best.
A large box placed over the plants from 5 p.m. until 7 a.m. might be the easiest way to provide the 14 hours of total darkness and still allow the owners to enjoy every room in their homes.
Keep placing the box over the poinsettias for the 14 hours from September until Thanksgiving when the new bracts will begin to show off their true colors.
(Editor’s Note: Ginny Rosenkranz is a commercial horticulture specialist with the University of Maryland Extension.)