Home > Great Big Greenhouse Blog > January 2015 > KEEPING THE HOLIDAY (PLANTS) ALIVE


Well, the parties are over, the ripped wrapping paper disposed of, ornaments packed safely away for next year…what to do with those poinsettias and other seasonal plants?

Poinsettia:  the most popular Christmas plant and the top selling potted plant in the United States, you can now pitch the plant onto the compost pile or keep it as a relatively attractive houseplant with the potential to color up again next December.  When the colorful leaves (bracts) begin to fade, many growers recommend that the plant be cut back and given a rest period of drier, cooler, and dimmer conditions.  In spring, when new growth appears, place the plant in a very bright to direct morning sun location (poinsettias will benefit from being summered outside in morning or dappled sun) and resume regular watering and fertilizing.  For a bushier plant, prune it back a couple of times over the summer, until mid-August.  Poinsettia flowers are induced by long nights, so beginning around October 1, start a “short-day” treatment, limiting the plant to only 8 or 9 hours of good bright light each day for six to eight weeks.  The other 15-16 hours each day should be dark (in a closet, under a box, etc.).  Any interruption in the plant’s long night may prevent bud formation.  Continue to water the plant as needed, but do not fertilize.  Once the bracts begin to darken or show color, the short-day treatment can be dropped, and the plant should continue to deepen in color.  If the plant is not exposed to a lot of supplemental indoor light in the evening, a poinsettia will naturally color up in late winter or early spring following the short days of winter.

Holiday Cactus:  popular holiday plants for over 100 years, the Christmas or Thanksgiving cactus (Schlumbergera x or Zygocactus) is an epiphytic cactus that lives up in trees in its native habitat.  It does not want to dry as much as a desert cactus, nor stay too wet since its roots are not adapted to wet soil.  After flowering, allow the plant to rest for a few weeks in cooler temperatures (50-65⁰F) and slightly less water.  Over the spring and summer, keep the soil evenly moist, not wet, and provide good drainage.  Fertilize with a flowering formula every two to three weeks.  Plants will benefit from the higher humidity of a summer outside under the trees.  In the fall, keep plants cooler and drier.  Shortening day length and cooler nights will usually induce flower buds that open around Thanksgiving.  Kept inside with a short-day treatment beginning around October 1, it may flower for Christmas.  Flower buds take a few weeks to open, so be patient and do not expose the plant to wide fluctuations in watering or temperature while in this stage to prevent bud drop.  As with many flowering plants, Zygocactus prefer to be moderately pot-bound.  Left to its own devices, the holiday cactus may flower in late winter or early spring following the short days of winter.  These plants can live for many years, and are often passed down from one generation to the next.

Cyclamen:  the common name Alpine Violet refers to the fact that this tuberous plant, native to the Middle East, is adapted to a cooler, sunny hillside existence.  The florist cyclamen is a cool season bloomer, available from September through March.  It does best in a cool (50-70⁰F), sunny window (east- or west-facing is best), and needs regular fertilizing to keep new flower buds coming.  Allow the soil to dry on the surface between waterings, avoiding water on the center tuber and never allowing the plant to stand in water.  The plant will begin to die back in March or April, and it will benefit from a rest period.  Store the tuber in a dry, dark location for three or four months.  As an alternative, some people plant the tuber in a lightly-shaded, well-drained bed in the garden for the summer, with the top of the tuber just showing.  Either way, repot the tuber in fresh medium in late summer or early fall, and resume normal care.  A larger pot is only required when the tuber grows too big to fit its current sized container, and transplanting should be done during the dormant or rest period.  Cyclamen tubers are toxic if ingested.

Amaryllis:  a tropical bulb, not winter hardy in our area.  When flowers fade, cut the flower stem off, but do not remove the leaves.  Keep the plant in a bright window, water when the surface soil is dry, provide good drainage, and fertilize regularly over the spring and summer.  The leaves and bulb will make and store the energy needed for next winter’s blooms.  If you fail to fertilize, the bulb will start to use the stored energy, and be unlikely to bloom again.  At the end of the summer, allow the bulb to rest by letting the soil dry out.  Remove the fading leaves, and set the pot on its side in a cool, dark, dry location for about eight weeks.  Start the flowering cycle again by repotting the bulb in fresh peat moss and giving it light and water again.  In a few weeks, a new flower stem will appear.  Given good care, an amaryllis bulb should get larger every year, producing more and more blooms each flowering season.

Norfolk Island Pine:  named for its native Norfolk Island, a tiny island in the South Pacific, the symmetrical shape and soft green needles make it and attractive plant for year-round use.  Bright indirect light to some direct sun will help the pine keep its “Christmas tree” shape, rotating the plant ¼ turn weekly to maintain symmetry.  Allow the soil to dry slightly between thorough waterings—do not allow roots to stand in water.  This houseplant will tolerate temperatures in the upper 40’s, but prefers moderate temperatures between 55⁰F and 75⁰F.  Apply a general houseplant fertilizer monthly, March through September.  Norfolk Island pines have small, fine root systems, and a 2-3 gallon container size plant  generally needs potting up to the next size every three to four years (4” and 6”pot pines may need potting up sooner.)  Dry air can cause leaf drop or leaf browning.  Lower branches will turn yellow or brown if kept too dry, upper branches will turn a crispy gray-green if kept too wet.  Do not prune unless necessary to control height, as it may result in asymmetrical new growth.

Paperwhite:  a tropical bulb that can be grown in soil or water.  Once the flowers have faded, the paperwhite (Narcissus tazetta) should be discarded.  It is very difficult to maintain and re-bloom, and loose or potted bulbs are readily available each holiday season.
Posted: 1/15/2015 by Margot | with 0 comment(s)
Filed under: MargotGunn, TheGreatIndoors
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