Phyllis Heuerman
Frederick County Master Gardener Program

With the holiday season upon us this is a good time to review care of two common holiday plants - the Poinsettia and the holiday or Christmas cactus.

The Poinsettia originated as a wildflower native to Mexico. The Aztecs put the plant to practical use, extracting red dye, and also using the milky, white sap, today called latex, to treat fevers. Joel Roberts Poinsett, the first ambassador to Mexico, brought the Poinsettia to the United States in 1835.

The colored petals that we call the flower on the Poinsettia are actually the bracts, or the leaves immediately below the flower. The true flower is the yellow part in the center of the bracts.

Poinsettias are easy to care for, but here are some tips. If all you want to do is keep the plant nice for a few weeks over the holidays, it is fine to keep it on a coffee or end table where it gets no natural light. But if you want to prolong its life and beauty it will have to have natural light most of the time.

Poinsettias prefer bright indirect or filtered light. This means a northern or eastern exposure, or behind a sheer curtain. They will not last as long in bright southern or western exposure.

Poinsettias prefer temperatures around 65 to 70 degrees during the day and 60 degrees at night. Home temperatures are generally fine as long as the plant is not in a hot, sunny window or on top of a warm appliance like a television. Poinsettias do not like to be in drafts or near heat vents.

You should allow the soil of a poinsettia plant to get semi-dry between waterings. Drain off excess water. Average home humidity levels are fine. No fertilizing or feeding of Poinsettias is necessary while the plant is blooming.

It is possible to keep your Poinsettia for rebloom year after year; but it is a bit of work. If you want to try, you should keep it growing until May. (You may take it outdoors when all danger of frost is past.) Cut the plant back in May. Each time it grows about 4 inches cut one-half of the new growth off. Water lightly and feed once a month with general-purpose fertilizer. Do the final cutting back of new shoots in August. Bring the plant inside in September. From late September until the end of October, while flower buds are setting the plant must receive 14 hours of total darkness at night. Even a little light will set the plant's flowering back or prevent it from flowering.

Another common holiday plant is the holiday or Christmas cactus (Schlumbergera).

There are many related cacti that bloom anywhere from October until Easter. You will hear them called Thanksgiving, Christmas or Easter cactus. Due to hybridization they are now difficult to distinguish. These cacti are native to the tropical rain forests of South America. In nature they grow on trees and shrubs, their roots serving as a means of secure attachment to the host.

If you have ever grown a Christmas cactus, you know that they are pretty easy to grow, but it can be tricky to get them to bloom every year. First of all, if you buy the cactus in bloom, do not allow it to be in a draft on sit in a cold car to long on the way home. All of the flowers and flower buds will drop off and you will have no flowers that year.

Christmas cacti should be grown in direct sunlight. However, during the summer when light intensity is high, the plant may need protection from the midday sun, which can burn the stems. Average house temperatures and humidity are fine, but avoid drafts and rapid changes in temperature, especially when buds are on the plant.

Christmas cacti should be watered when the soil feels dry to the touch. Drain excess water from the plant; too much water will make them rot. They should be fed every two to three weeks from right after flowering until fall when they are setting new flower buds.

Both temperature and length of the day affect flowering of Christmas cactus. Flower buds will form:

" Regardless of length of day if the night temperature is maintained at 50 to 55 degrees.

" If the temperature is between 55 and 70 degrees, 13 hours of uninterrupted darkness will result in bud formation.

" If the temperature is above 70 degrees, 15 hours of uninterrupted darkness is needed.

The above conditions must exist for 9 weeks, starting in early to mid September. You can create dark conditions by placing the plant in a room that does not receive artificial light, or covering it with a dark cloth, or putting it in a closet at night. Do not give the plant 24 hours of darkness.

Read other winter related gardening articles