What Do We Mean By "Native"?

2/5/12
Palo Verde tree, native to southern Arizona
     I don't know any gardeners that have only native plants in their yards or gardens, although there are gardeners probably striving to grow only natives.  But defining what we mean by native is challenging.

     Many gardeners accept only indigenous plants as native.  Gray's Anatomy of Botany says that to be indigenous there must be scientific evidence that the species has inhabited an area for a great length of time, that it's an integral part of local, evolutionary relationships with other plants and animals.

Saguaro cactus, native to southern Arizona
     But what is a great length of time?  Thousands of years? Hundreds of years?  For example, there were plants that were present in an area of the globe before a glacial period, different plants that were present during a glacial period and different plants after a glacial period.  Can all be considered native?  When European colonists arrived in the Americas hundreds of years ago and introduced species that live on unassisted today, are these species considered native?  If a plant has  become naturalized as a member of the wild flora, needing no human assistance in self-perpetuating, can that plant then be called native?  What of an indigenous plant that migrates to a new area and becomes naturalized without assistance?  Is native a function of time and place?

Lantana, not native to southern Arizona
      Situations like this occur all over the world.  If native status is a function not only of time but also of place, defining place can be a perplexing.  There can be dramatic differences in habitat within a relatively small area.  In my own state of Arizona, within a twenty mile distance, you can go from desert habitat to tundra.  And the plants in the tundra habitat in Arizona are the same as the plants in the tundra of Alaska.

     And consider what we call invasive plants.  They would not exist unless they were better adapted to current conditions than so-called native species.  As Richard Darke says in the book The New American Landscape, " ...most natives are no more than earlier arrivals that established themselves because, at the time, they had a competitive advantage."

gazania, not native to southern Arizona

     Non-native plants fulfill roles that can't be accomplished by natives.  Many food plants grown in North American gardens do not have their origins here.  Many flowers that gardeners grow are not indigenous to their area, but provide beauty, fragrance, color and pleasure, such as the lantana and gazania pictured above that I grow in my yard.. 

     Most gardeners realize that no garden or landscape remains static, that local and global ecologies change.  In the end, I think most gardeners strive for balance among all their plants.

6 comments:

  1. Such an informative post. This post reminds me of how surprised I was to learn that groundnuts were introduced to India quite recently. We have so many traditional Indian groundnut (peanut) recipes that I couldn't imagine that. And when I learnt that lemons were native to India, that surprised me too, since though we use lemons, we don't do anything much with them. I think what qualifies as native and non-native is something only scientists can tell us.

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  2. L, I like your thought-provoking look at a strangely contentious issue. I suspect most gardeners, if pressed, would have to agree that there are "good" natives and "bad" natives and good non-natives. And that, as you conclude, balance is key.

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  3. Anita,

    I think many of us have been surprised that a plant we thought was native was "recently" introduced, but then, again, deciding what is considered native is an issue.

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  4. Lee,

    This is a contentious issue, and I can appreciate the many viewpoints on this. But, for me, balance is the most realistic answer to all the complexities of this problem.

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  5. The plant kingdom is so much like ours - natives and live harmoniously among non-natives. The daily fights, struggle for survival and co-existance happens between natives and non-natives among members of their own kind.

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  6. Autumn Belle,

    I never thought about this when I was writing the post, but, yes, this is true also.

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