My recent post on Seattle Public Utilities proposed restriction on the use of non-native plants for landscaping drew the ire of Taryn Evans of the Florida Native Plant Society. Taryn was critical not only of what I had to say but how I said it. She felt that my post was ‘clumsy’ and lacked a clear focus. In my defense, part of the perceived lack of clarity may stem from a lack of context. I alluded to several previous blog posts (including the references to using goats and schoolchildren to control invasives) but didn’t include the links – which are now listed at the end this post.
In terms of my other points, let me state my views as succinctly as possible.
I support promoting the increased use of natives in landscapes as part of an overall effort to increase landscape diversity and stability. Part of this is based on the notion that a diverse landscape –including natives – is buffered against various environmental and biological perturbations. But I also support natives because they provide a linkage to our native environment or sense of place. This second argument, by the way, is adopted by the California Native Plant Society http://www.cnps.org/cnps/about/ but is dismissed by Tallamy who states that his argument for native plants “moves beyond debatable values and ethics and into the world of scientific fact.”
I do not support legal restrictions that mandate the use of native plants in landscapes
Here are my concerns:
– The “scientific facts” regarding natives are not universally accepted by ecologists and are subject to debate as well. http://www.nature.com/nature/journal/v474/n7350/full/474153a.html#/ref8 A species’ need for water/nutrients/pesticides is a function of the environment in which the species evolved and not necessarily a native/non-native question. Invasiveness is an undoubtedly an issue, but exotic does not mean invasive. Some will argue that we can hedge our bets and prevent future invasions by planting only natives. And that is a justifiable position – I don’t agree with it – but I accept it as a rational argument. The dilemma with banning all exotics is that we throw the baby out with the bathwater and risk eliminating many useful plants.
– Natives can make great landscape plants in the right place but in many cases they are poor choices, especially in the built environment. Consider some of Tallamy’s recommendations from “Bringing Nature Home”:
Cottonwood. Cottonwoods are banned by many tree ordinances for their mess (cottony seeds and sticky buds) and are weak-wooded.
Maples. Maples are great landscape trees but we need to consider the fact that they are already overplanted in many communities. If we look at street trees and other public trees, maples make 50% or more of the tree population in some cities and towns. Does planting more make sense in these situations?
Ashes. Maybe if you live west of the Rockies, otherwise they’re a non-starter.
Lindens. Lindens have great form, growth rate and color. Unfortunately they are candy to Japanese beetles.
Elms. A handful of Dutch elm disease tolerant cultivars of American elm are available but the vast majority of trees available are Eurasian hybrids.
– Plants, especially trees and shrubs, evolve slowly. If we accept current climate predictions, trees planted today may experience very different climates in their lifetimes than those under which they evolved. The widespread outbreak of pine beetle (a native pest) in the Mountain West that is destroying millions of acres of pines could be an early indicator that changes in climate are already increasing stress levels and reducing the fitness of native trees.
Taryn was also critical of the tone of my post. For me and my co-bloggers this space is the editorial page of our lives. The blog is an opportunity to let our hair down a bit, vent on pet peeves, and sometimes shoot from the hip and play agent provocateur. No one likes to be criticized but it comes with holding our ideas up to public scrutiny and I accept that. I should note, however, that as the native debate moves from advocacy and education to codes and regulation, native advocates need to brace for increased criticisms and have their logical and scientific ducks in a row – which is the take-home theme of my post. Let’s face it, my critique was mild. As seen in the repsones to my post, some are quick to politicize or label the native case as disingenuous. Others would go further still and have labeled nativists as reactionaries and xenophobes (See http://arnoldia.arboretum.harvard.edu/pdf/articles/646.pdf or wade through David Theodoropoulos’s “Invasion Biology: Critique of a Pseudoscience). Obviously this is taking the argument to a ridiculous extent. I’m all for a fair debate where we can question statements and ideas but not motivations.
Earlier posts:
I read Tallamy’s statement as inclusive not dismissive of sense of place. “…moves beyond debatable values and ethics and into the world of scientific fact.”
In my opinion, he is not basing his case for native solely on subjective arguments such as sense of place, but he’s adding other, more measurable results.
Many readers of The Garden Professors have an expectation that a Washington State University blog post will contain information that is wise, scholarly, presented in a clearly understood manner, and that all opinions, even if they are expressed in the form of a rant, are backed up by facts, educated hunches, or intellectual dissent. That a reader found one of your posts clumsy and unfocused attests to the fact that this might not be the best venue for letting one’s hair down or shooting from the hip. The above follow-up post, on a subject that is controversial, makes a powerful argument.
I think this is a good blog for this discussion as well from the standpoint of why do gardeners use native plantings anyway.
http://landscapeofmeaning.blogspot.com/2012/08/garden-designer-roundtable-designing.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+GroundedDesign+%28grounded+design%29
I believe that a key point in discussing natives is that they provide a valuable component to a mixed environment. That mixed environment is what exists for most gardeners and often times our remaining stands of forest. If you considered that ivy and blackberries have moved into suburban green belts and those forest lands close to suburban we see a polluting of the native habitat.
Here in the Pacific Northwest(PNW) we also have to consider a change in the climate and how dry it is becoming. I have seen this in my own yard for the last 5 years and have changed my plants to accommodate that change. Some of my natives have died out because of this weather change. In some cases I have been able to bring native plants from Eastern Washington to Western Washington where they are thriving.
I get concern when legal guidelines start becoming mandatory for native plants because at least here in the PNW they require overhead plants to support them. When developers consistently use the practice of taking topsoil away so they can build easier,it does not help any growth come back easier. So maybe the real root of the cause and effect here is a change in building practices in that support the reapplication of soil that was moved aside to build what building was built.
A second approach is to encourage the use of natives in building project and like everything, it is about education. Showing the value of natives in the environment and building a mixed environment is a lot healthy for everyone.
A correction and a comment to Allan’s comment. First, this is not *just* a Washington State University blog. It’s simply housed on a WSU server. But if WSU had a problem with the content of the blog, they would certainly let me know.
Second, I disagree that this is not a good venue for the four of us to editorialize. Our opinions are backed by facts, but science – especially in newer areas such as invasion biology – is not as clearcut as we may like it. We often take issue with each other’s opinions, but our exchanges are professional and fact-based. They’re not personal.
This is where Taryn crossed the line. She made it personal, not only with her criticism of Bert, but of me as well. (For those of you who didn’t read the Florida Native Plant Society post, she criticized me for blogging about the issue rather than attending the public meeting in Seattle. Had she bothered contacting me directly, she would have found out that I was presenting a seminar at the ISA conference in Portland at that time.)
Let’s continue to discuss the science and move forward, rather than resort to personal attacks.
Thanks Linda, forgot to add those excellent comments.
In the meanwhile, because the discussion of native plants is important to me and this group as well as contributing to the economy of Washington State. So not only science but economics play a huge role in native usage.
I also get Val Easton’s blog and thought I would share on this post, her contribution to this topic.
http://www.valeaston.com/2012/08/seattles-proposed-new-green-codereally-75-native-plant-mandate.html
The regulations show a lot of good intentions, but not much thought. What does 75% native mean; 75 tiny star flowers and 25 exotic trees? Native where; North America, western Washington, the Puget Sound basin? Are these decisions left up to the sole judgement of the individuals approving the planting plans? What are their qualifications for making these decisions?
Sounds like a perfectly reasoned defense to me that I agree with, Bert. Someone ought to say that (and I’m pretty peeved that my city of Lincoln keeps planting trees and sod, but no prairie plants–some “prairie capitol” we are).