Plant Care Articles

Poinsettias are known for their holiday appeal.  Their vibrant reds and greens remind us of the holidays so much that December 12^th is known as National Poinsettia Day across the United States.  Poinsettias fly off the shelves in places ranging from your typical garden center to the local drug store.  Often times, these little plants are given as gifts during the holidays, but this produces a problem for the new owners of the festive plant.  “How does one take care of these plants?”

Taking care of Poinsettias is normally not a problem because they grow as compact little plants that can be easily handled and that do not need much light or water to grow…right?  Well, that’s not quite right.  If left to their own devices in an environment that is suitable for their cultural needs, Poinsettias can grow to be just over 15 feet tall and grow as shrubs or small trees.  One of the first problems that gardeners come across when they care for their Poinsettias after the holidays is the plants get “leggy”.  This means they grow long stems and their leaves are not as tightly packed.  Commercial Poinsettia growers use several techniques to make their Poinsettias look the way they do when they reach the store shelves.

Since Poinsettias naturally grow much taller than how they are commercially sold, they are treated with Plant Growth Regulators, also known as PGRs.  These compounds restrict the height of the plants so they fit better in their tidy, film-wrapped pots that are ubiquitous in stores during the holiday season.  This explains why a Poinsettia will quickly have a growth spurt after the average gardener takes over the plant care from the commercial grower.  The PGRs are no longer being applied to the plants, and the Poinsettias revert back to their natural, vigorous growth.  This does not mean that Poinsettias are entirely unsuitable for the average garden.  The height of the plants can be controlled by pruning back the primary stem at least once per month.  This will increase the bushiness of the plant and will limit the overall height.  Do not do any pruning after the middle of August to be sure the floral buds are not also removed.

When Poinsettias flower they produce specialized leaves called bracts that subtend the actual flowers.  Bracts are what provide the contrasting colors that Poinsettias are prized for.  Unfortunately, the end of the holiday season also marks the beginning of the degradation of the contrasting colors.  There is little that can be done to preserve the current year’s blooms, which means you should focus on next year’s flowers.  Poinsettias require long nights to initiate their floral buds.  This means that the period of dark cannot be interrupted with any source of light at night.  Poinsettias in nature use the lengthening nighttime to trigger flowering.  Artificial lighting in houses can disrupt the long night and prevent floral bud initiation.  To counteract potential light pollution, a potted Poinsettia can be moved into a dark closet at night and removed at 8 AM.  This method can be tedious and labor intensive for the average gardener.  In warmer climates where winter freezes are never a threat, nature can takes its course and trigger the flower initiation for you.  However, if there are any sources of artificial light that are on at night, you will have to cover the Poinsettias with shade cloth at night to prevent the long night disruption.  Once again, this is labor intensive and another reason why Poinsettias are difficult to force to flower.

To get Poinsettias to flower on time for the holiday season, the timing has to be just right as well.  Poinsettias need around 2 months of nights that are 15 hours long and uninterrupted.  Poinsettias that are grown indoors and in pots are the easiest to manipulate the light for.  Starting the first week of October, place the potted plant in a dark closet at 5 PM every night.  Return it to its usual sunny spot at 8 AM the next morning.  This needs to be done every day until the end of November.  Starting this lighting regime in October will provide color for the holiday season.

Other than being difficult to initiate flowering, Poinsettias are fairly easy to grow.  Keep the soil or potting mix moist but not wet.  Avoid strong air currents, which can include windy spots in outdoor gardens or heating/cooling vents for indoors.  Provide bright light.  There is a reason why Poinsettias grow to be around 15 feet tall.  They are stretching for the sun.  Poinsettias do best with bright light regardless if they are kept short by constant pruning or with the use of PGRs.

Poinsettias are primarily sold as small potted plants during the winter months, but that does not mean they have to be thrown out after the holidays.  Since Poinsettia plant care is relatively more involved than most other ornamentals, most people will toss these plants to the side.  If the gardener is willing to put in the extra effort, their Poinsettia can live for a long time and provide holiday color year after year.