Thursday, January 6, 2011

Myths about Native Plants

I am a passionate advocate of native plants.  And I’m not the only one.  Native plants are as popular now as ever, which may explain why there are so many misconceptions about natives.  So I wanted to dedicate a few postings to busting some myths about native plants.  Now to the first myth.

Myth #1: Native plants are more drought-tolerant than their exotic counterparts.
One of the top reasons people give for using native plants over exotics is that natives are more tolerant of drought than their exotic counterparts.   You hear this claim spread even by knowledgeable gardeners and horticulturalists. 
Hibiscus in its native wetland habitat
Here’s the problem: it’s simply not true.  At least not as a categorical statement.  
Why not?  The claim is based in the assumption that plants in their native habitats do not require artificial watering; therefore, native plants are more drought-tolerant than exotic garden plants.  The problem with this assumption is that native plants refer to any plant indigenous to a local area.  This includes mesic (wet-loving) plants and xeric (dry) plants.  So if you are to compare a wet-loving native Rose Mallow (Hibiscus moscheutos), for example, with your average Japanese azalea, the azalea would be more drought-tolerant.  Native plants are too broad a term to categorically say that they are more drought tolerant than exotics.  Some natives are tolerant of drought; others are not.
The other practical problem with this assumption is many of the most popular natives sold in the nursery trade originate from moist ecosystems.  Why?  The nursery trade focuses on the most ornamental natives, particularly floriferous forbs and shrubs.  The problem is that, as a general rule, plants with lots of flowers are evolved to compete in moisture and nutrient rich environments.  Plants in drier environments must save their resources and flower only under ideal conditions. 
And this is one reason natives get a bad rap.  Neighbor Susie reads on the internet that native plants are more drought-tolerant.  So she goes to her local nursery and selects a beautiful blooming Cardinal Flower (Lobelia cardinalis), which the nursery guy told her attracts hummingbirds.  So she goes home and plops in her Cardinal Flower next to her Russian Sage (Perovskia atriplicfolia).  Of course, the Cardinal Flower is native to moist bottomlands and dies within a matter of months once Susie goes on vacation in August.  Susie looks at her vigorous Russian Sage and decides natives are too fussy and weak. 
What people mean to say when they make this claim is that plants perfectly suited to their environments are more drought tolerant than plants that are not.  The issue is not about native or exotic, but about pairing the right plant with the right environment.  Just because a plant is native to your local region does not mean it’s better adapted to your yard than an exotic.  It helps, of course, but gardeners need to match the plant’s ecosystem of origin with its new environment.   
If it sounds like I’m making an argument against using natives, I’m not.  There is a wonderful native plant for almost any condition in your yard.  It just needs to be the right plant for the right spot.    


Native plants on the Washington D.C. sidewalk in the blazing heat of August, IFC Building.


9 comments:

  1. Great post Thomas, can't agree more right plant right place.

    I always recommend reading about the particular habitat that a plant originated from or observing it in nature. It is the key to success for natives (and ornamentals) in your landscape.

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  2. Oh how I fell for this myth years ago, assuming lobelia would be fine in dry shade - after all it's native. Killed quite a few til the penny dropped - now it's happily situated in a damp meadow. Thanks for this - looking forward to future myths...

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  3. What a pedagogically perfect posting.
    I hope you save such posts for a book that you might publish one day.

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  4. Good points - people should preface "native plant" with "drought-tolerant", "cold-requiring", etc.

    Here, many use native riparian trees (cottonwood, ash, etc) with native desert upland shrubs (cacti, etc), with the same failed results you stated - and the same public negative reaction. But change the trees to native, upland species (mesquite, juniper, oak, etc), and success!

    The same thing is useful in expanding to non-native adapted plants - discern analogous climates, then soil types, moisture regimes.

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  5. This is such a good post...I'm glad someone finally came out and said it! I always roll my eyes when I see people pompously announce they are planting ONLY native plants in THEIR garden, you know, because they care. Then they tell me the plants they are growing and i want to say "Umm...your parking strip in the middle of a city isn't exactly like that plants native environment...you know, stream beds and forest edges." I love natives, but only in appropriate conditions...as you said, Right Plant, Right Place.

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  6. Thomas, Thanks for another great article. I agree there is a lot of mis-information out there about using native plants. And there are lots of 'Neighbor Susie's who are just trying to grow a colorful garden and don't realize there's more to it than planting it and forgetting it.

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  7. The average person, gardener or not, not only does not know endemic/native/exotic, but anything else in terms of biodiversity and the wise manner of designing: not necessarily from common place nurseries, but from what the immediate surroundings, microclimate will
    allow to flourish without much or any high maintenance.

    Excellent post.

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  8. Hi, master gardener in Florida here and I've noticed a disturbing trend the last year or so toward this almost uncompromising allegiance to native plants AND the non-use of chemicals. Right plant, right place always no matter where the plant originates. Also, in IPM, you start with the lowest impact and if that doesn't work move up. Chemicals have their place to be sure. If people have a real problem and don't want to use any chemical, then they must accept their plants will be compromised. Another pet peeve, the belief that going native means your yard must look like a jungle a la the Hormel commercial with the goat on the roof. Good landscaping principles apply regardless. Funny thing too that people have this image of what a 'natural' environment looks like (jungle) when it often doesn't. It was said at one time you could ride a horse from the mid-Atlantic states to Texas under pines with no shrubs. All this being said, I do like to use natives whereever possible because so many are threatened in their natural habitat. Just don't care for this absolutism that's going on in landscaping here.
    Definitely going to bookmark this site. Excellent post, thx.

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