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Plant of the Week
Desert Sun Lantana
Latin: Lantana camara
'Desert Sun'
Winter arrived early over the weekend with freezing temperatures as far south
as Birmingham, Ala. By my reckoning -- at least according to our recent winters
reminiscent of those normally encountered in the banana belt -- it arrived about
a month early.
Saturday morning, after the dip to near freezing temperatures, it was easy to
spot the plants with a tropical birthright and those with more temperate
upbringing. The warm weather plants, such as lantana, were already looking
forlorn and starting to turn black.
Lantana, a member of the verbena family, is a woody shrub native of tropical
America that has long been cultivated as a garden plant. In the wild it can make
a bush 6 or more feet tall, but in our gardens it is seldom seen more than a
foot tall and perhaps 2 feet across. Some plant forms have a more decidedly
upright habit while others are more trailing.
Flower color of ‘Desert Sun,’ is predominately orange, but the tiny
trumpet-shaped blossoms go through a range of colors from the day they open
until they fall off three or four days later, giving the 2- to 3-inch diameter
flower heads a tri-colored appearance.
Lantana leaves are typical in shape with an ovate outline and a serrate margin
and can grow 3 to 4 inches long. They are rough to the touch and aromatic when
crushed, betraying the family’s close relationship to the mint family. When
exposed to temperatures in the mid 30's, lantana leaves turn from their lusty
green to gray-green and finally black.
Lantana, and in fact most plants from the warm tropics, turn black when exposed
to temperatures well above freezing due to a phenomenon called "chilling
injury." Just as a banana will turn black when placed in the refrigerator, these
tropical landscape plants simply abhor the cold.
The reason chilling injury occurs, is because of the makeup of the cell
membrane. Membranes are composed of a complex mixture of lipids and starches and
are wonderfully sensitive mechanisms for holding the juices of life inside the
cell and still permitting the orderly transfer of things in and out of the cell
on an as-needed basis.
In tropical plants, the lipid component of the cell membrane coalesces as the
temperature drops, creating tears in the cell membrane allowing the stuff of
life to leak out of the cells. Many tropical plants show signs of chilling
injury whenever the temperature drops below 45 degrees.
Plants from a temperature climate have adapted mechanisms to permit the
membranes to function at colder temperatures. In super hardy trees from the
timber line on mountains, the membranes can be protected to as low as minus 40
degrees F.
If your lantana froze back before you were able to collect cuttings for next
year’s planting, don’t despair. While the leaves wither up and die at the first
sign of cold weather, the stems are more freeze tolerant.
Many gardeners dig up choice plants, cut them back hard and then overwinter them
in a bright location over winter. But, for a couple bucks, a wide assortment of
new, vigorous plants are available from local nurseries in the spring so such
effort seems hardly justified in today’s busy world.
By: Gerald Klingaman, retired
Extension Horticulturist
- Ornamentals
Extension News -
October 13, 2000
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