The last few years have seen a resurgence in the
popularity of "native" plants. Common sense tells us that native
plants—plants that have always grown in a particular habitat—are better adapted
and won’t cause trouble like some "exotic" plants have. For example, in
many southern states kudzu is considered a weed—and a tenacious one at that. Kudzu (Pueraria
lobata) is native to Japan, southeast Asia, and some Pacific islands. It was brought
to the U.S. and widely planted for erosion control and as a forage crop, but has become
invasive and difficult to eradicate. Water hyacinth is another example of an invasive
exotic, originally introduced via the horticulture trade.What might surprise you is how few common garden plants are
actually native to the U.S. Before humans came on the scene, plants rarely traveled
between continents—only if the seeds or plants were carried by wind, water, birds, or
other such means. With the advent of intercontinental travel—and this dates back
hundreds of years to well before Christopher Columbus—the number of exotic plants
introduced to this country has soared. Some plants were intentionally brought for use as
food or ornamental crops; other plants were inadvertently transported as stowaways.
Here are the origins of some common
vegetable and ornamental crops:
Africa: watermelon, gazania, cockscomb, impatiens, basil,
sesame, leek, asparagus, coriander, statice, narcissus, English ivy
Australia: strawflower, New Zealand spinach, winged
everlasting, swan river daisy, blue lace flower
South America: tomato, potato, nasturtium, fuchsia, some
types of winter squash, begonia, cleome, petunia, portulaca, heliotrope
Central America: marigold, Mexican
sunflower, some types of winter squash, ageratum
Mexico: tomatillo, cosmos, dahlia, zinnia
Japan: chrysanthemum, balloon flower, wisteria
Russia: delphinium, globe thistle, speedwell, baby’s
breath, yarrow, centaurea, scabiosa
Turkey: lamb’s ears, hollyhocks, bells
of Ireland
East Asia: rhubarb, sweet potato
Asia Minor: apple
Southern Europe: artichoke, Florence fennel, larkspur,
burning bush, stock, candytuft, rosemary, sage, snapdragon
One particularly interesting "exotic" is the
honeybee. Many important food crops are almost entirely dependent on the honeybee for
pollination. Yet the honeybee is a fairly recent introduction to North America. Europeans
brought honeybees to the New World because they were efficient pollinators and, due to
their social nature, were relatively easy to manage in manmade hives. And they produced
honey to boot!
When we think of bees, we usually think of the
honeybee—but there are more than 3500 species of bees in the U.S., and most of them
play the role of pollinator. As the population of honeybees declines due to disease and
mite infestation, these native pollinators will play an increasingly important role in the
pollination of both cultivated and wild plants.
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