Native Plants

Master Gardeners advocate landscaping with native plants. Since the spring planting season is upon us, I thought it might be fun this month to take a look at what the Web has to say about landscaping with natives.

What is a native plant? For starters, we can assert that native plants must be plants that grow "wild" but that's not the only requirement. Some plants that grow in the wild are not native. A perfect example in our area is Lehmann's lovegrass (Eragrostis lehmanniana) which grows profusely in this area but is not native here. It is a South African plant that was introduced by cattlemen less than 100 years ago to provide range grass for cattle. Since that time it has become naturalized and spread widely, choking out some of the true natives. The standard definition of a native plant requires not only that the plant grow naturally in the wild but also that it has not been introduced by humans... or at least so far as we can tell.

Left to themselves, plants in nature over generations migrate slowly from place to place to accommodate themselves to changing environments. The slow pace of this migration means that the plants bring their enemies along with them - insects, diseases, and competing plants. When humans speed up the process by transporting seeds or living plants across long distances, the enemies usually get left behind. One of the dangers of introducing exotic plants into an environment is that without natural enemies, they may take over an area. Such plants are said to be invasive. A good example for those of you who have traveled in the South is the kudzu vine which was brought from Japan in the late 1800's as an ornamental. Finding itself in a favorable environment and without any natural enemies, kudzu has spread a smothering, green mantle throughout the South, covering 2 to 4 million acres and killing entire forests. In addition to killing off local vegetation, invasive exotic plants also destroy wildlife habitat. Less dramatic but a little closer to home, is the popular ornamental fountain grass (Pennesetum sp.) that naturalizes in our area and often becomes a nuisance.

Fortunately, most of the plants available from commercial nurseries do not threaten us with a massive kudzu-type invasion. This is because plants are carefully screened before they are placed in the commercial trade. The greatest danger of creating a green invasion comes from the accidental introduction of exotic species when seeds or spores hitchhike a ride into an area or the deliberate introduction by people who travel to other areas and bring exotic plants back with them. Although the danger of introducing an exotic pest is a good negative reason to stick with natives, there are some positive reasons as well.

From the gardener's perspective, the best reason for landscaping with native plants is that natives require much less care and maintenance than most non-natives. Most of the non-native plants that people attempt to grow are just not adapted to our soils and climate. Plants that are not used to the high temperatures, low humidity, and alkaline soils found here in Cochise County have to be kept in botanical equivalent of intensive care for their entire lives. This means that the gardener is constantly fighting with nature to keep the plants alive. Native plants have chosen this area to grow in because they like the local environment. They thrive in alkaline soils and have developed mechanisms to deal with the heat and dryness.

Another, more subjective, reason for choosing native plants is that they look like they belong here while many non-natives don't. Alpine vegetation looks good in the mountains and jungle plants look good in a rain forest but neither look very good in Cochise County, Arizona. If you really like living here, why try and make it look like someplace else?

The last reason to go native is for the animals that live in this area. They are adapted to the native vegetation which provides them with food, protection, and nesting materials. If you like birds and other animals in your yard, plant native.

If you are interested in this subject and would like to learn more, do a Web search on "native plants." My search on AltaVista gave more than 16,000 hits. Some specific sites that I found interesting include: www.nfw.org/nwfihabitats/workplace/natives, www.maxinet.com/garmour/cnpsml2.htm, noumenon.cfa.cmu.edu/nmr/research/nativeplants.html, lgx.com/Native.Plants/, and www.flsun.com/wildlife/lookback.htm. Another interesting site is the Arizona Native Plant Society at www.azstarnet.com/~anps/.

Happy surfing!