eGarden © 2008 Ed Mues

December 17, 2008

Peace and Light

This is my wish for you this holiday season and for the coming year. The light is metaphorical, of course. It is also reality to a host of seasonal flowering plants at this time of year. The appearance of Christmas plants each year isn't always about flowers.

The Norfolk Island pine, ivy, holly, mistletoe, wreaths and evergreen boughs and trees impart a freshness and festive atmosphere with their greenery, colorful berries, and fragrant cones and foliage. But, I'm going to focus on winter flowering plants, today.

With the shortest day of the year only four days from now, the poinsettia about which I wrote last time could not perform as expected if it were not for the long nights (short days) that the season affords.

Plants bloom and set seed according to the length of the photoperiod, that is, the amount of light they receive in a given space of twenty-four hours. At this time of year, short-day plants like the poinsettia, flower under a shorter photoperiod. There are long-day plants that are responsive to long photoperiods and a third group, day-neutral plants, which are not responsive to changes in photoperiod.

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Rex begonias are rhizomatous and are grown mostly for their colorful and beautiful foliage, rather than their flowers. An instant hit as a gift, they prefer warm temps and the higher humidity of a kitchen or bathroom with a nearby window.

Research into photoperiodism began more than 60 years ago when the existence of short-day and long-day plants was discovered. It turned out that it is not the day length (light period) that is decisive for stimulation of flowering, but the night length (dark period). In 1945 scientists learned that red light played a very important role as did the presence of a substance called phytochrome, localized in the leaves and required for the control of flower formation.

There are unique, evolutionarily inherited traits involved in photoperiodic flowering at the most basic molecular level. This is all rather complicated and temperature plays a separate role, as does the absorption of red light (maximum wavelength around 600 nanometers) and far red light (maximum wavelength around 720 nm). Researchers have further speculated that the ratio between hormones dubbed florigen and anti-florigen will determine the production or suppression of flower formation.

So, what does all of this scientific talk have to do with us? What short day (long night) flowering plants do we have around the winter solstice that we can bring home for holiday decoration or look forward to giving as a gift? Sure, there's the poinsettia discussed two weeks ago. Well, surprise, surprise, there are very many others including the Christmas cactus. What great colors are available!

I'm sure you're familiar with florist chrysanthemums, fragrant and colorful. Tender azaleas, as opposed to the hardy ones, provide great displays of color. The Kalanchoe blossfeldiana (Brilliant star, Scarlet gnome), an attractive succulent from Madagascar, is a winner and easy to grow. It, too, only blooms in winter and early spring.

Then there is Cyclamen with beautiful and colorful curving petals and gorgeous mottled foliage that performs well into April. A poinsettia cousin, Crown of thorns, is available in red, pink and yellow flowering varieties. At this time of the year you'll find Amaryllis bulbs in a variety of colors. You might even find Helleborus niger, Christmas Rose, if you search a bit for the cool spot in your home. They are not roses, but their blossoms resemble wild roses.

I must add a couple of others that are standouts. The Rieger begonia, developed in 1955 by Otto Rieger, is a popular and versatile houseplant with intense flower colors and different flower shapes. Beautiful salmons, reds, pinks, and yellows will brighten any room for several months.

Rex begonias, while short day plants, usually with lovely pink flower sprays, are more often grown for their extremely colorful and varied foliage. Once you become a fan, you'll seek out more and more varieties. They are very special and their spectacular foliage is present all year round.

So, go forth and search. There are many lovely plants available for indoor use at this time of the year, and the grower has taken on all the trouble so you can just bring it home and enjoy it.

From The Garden of Ed. Submitted for publication in The Towne Crier on December 17, 2008

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