Biodiverse Gardens are More Pleasing to the Eye

Despite publishing a scientific paper entitled 'Small scale additions of native plants fail to increase beneficial insect richness in urban gardens', I really am a huge fan and proponent of native plants and biodiverse gardens.  I just have a sense that the benefits of native plants (especially smaller shrubs and annuals) are oversold to home gardeners.  Not all native plants will use less water, better resist pests, or best attract wildlife.  And, gardeners are often left with the impression that they can install a few native plants to support local wildlife.  However, our results suggest that additions of 200-250 plants would be needed, to increase bee, butterfly or beneficial wasp richness by one species.

Given that a few plants won't yield strong benefits to native biodiversity, what type of gardening approach can help conserve wildlife?

A new paper by Petra Lindemann-Matthies and Thomas Marty (Does ecological gardening increase species richness and aesthetic quality of a garden.  Biological Conservation Volume 159,March 2013, pp 37-44) provides strong evidence that a whole gardening approach gets results.

They surveyed 36 gardens in Zurich, Switzerland, and scored them for the presence or absence of the following ecological features: 

• ponds (provide habitat for amphibians, aquatic insects, aquatic plants)
• flower meadows (provide nectar and pollen to a variety of beneficial insects, and host rodents that are food for birds)
• dry walls (provide nesting sites for beneficial insects, or insects that birds feed upon)
• nettle plots (provide nectar and pollen to a variety of beneficial insects)
• nesting sites for wild bees and birds
• decomposing piles of wood (provide habitat and nesting sites for a variety of beneficial insects)

and the following gardening practices:

• frequency of lawn mowing
• use of synthetic fertilizers
• use of pesticides
• frequency of weeding

A 'bee barn' at the Marion Garden in Salem, OR.

Beneficial Insect Garden at the Marion Garden ~ a demonstration garden of the Marion County Master Gardeners.

They created an 'ecological gardening' score for each garden, by assigning a '1' to beneficial practices (e.g. rarely or never using pesticides) and a 0 to non-beneficial practices (regular use of pesticides).  They then counted the number of plant, fungal and animal species within each garden.

Here is the good news!  Gardens with a higher 'ecological score' were more biodiverse, took less time to manage, and were judged more aesthetically pleasing by neighbors, compared to gardens with a lower 'ecological score'.

In fact, 67% of the variation in biodiversity among gardens was a result of the 'ecological gardening score'.  Only 35% of the variation in aesthetics was a function of the ecological score of each garden, which suggests that ecologically-friendly gardening practices have more of a positive impact on biodiversity, than on aesthetics.

You can learn more about ecological gardening practices by visiting Linda McMahan's ecogardening website, or by visiting an OSU Extension Master Gardener demonstration garden.  Locate the garden nearest you by visiting our Google Map of OSU Extension Master Gardener activities.

View OSU Extension Master Gardener Map in a larger map

Backyard Biodiversity ~ What's in Your Garden?

While researching potential speakers for the annual Gardener's Mini-College, I came across this lovely article in the New York Times, written by Carol Kaesuk Yoon.  I knew Carol from my time as a graduate student in the Entomology Department at the University of Maryland.  Carol's husband, Merrill Peterson (who is mentioned in the New York Times article), was a post-doctoral researcher in Bob Denno's laboratory, where I was working on my graduate degrees.

My time at Maryland was about as utopian as a graduate student's experience could be.  Our lab was fun!  Our field sites were a 3 hour drive from the University, and we often killed time by playing games where we took turns naming as many birds species, butterfly host plants, car models, cartoon shows, or anything else we could come up with.  If you couldn't think of something new to add to the growing list, you were out.  [File under: games nerds play.]

We also spent quite a bit of time talking about our various collections.  If you're an entomologist, it's nearly mandatory that you have a collection.  Bob and Merrill collected butterflies.  Merrill and Micky Eubanks kept birding lists.  Bob also collected:  coins, pine cones, lichens.  I really looked up to these smart and accomplished folks, and I wanted to emulate them.

So I started my own collection.

I collect cerambycid (longhorn) beetles.  Cerambycids are beautiful, and sometimes quite damaging.

A banded alder borer ~ one type of cerambycid beetle.  Image credit:  Larry Hanks.  Image linked to Science Daily press release at:  http://www.sciencedaily.com/releases/2008/08/080805153826.htm.

But once I bought my first house and started gardening, I also started to collect the insect species that visit my yard.  I don't collect every day, or even every week during the summer.  Basically, I collect on summer days when work gets overwhelmingly stressful ~ and I need to do something to calm my mind, but could still qualify as 'work'.

The bounty from an afternoon spent collecting insects in my backyard.

My secret goal is to document every insect species that visits my backyard garden, similar to the classic A Natural History of New York, by John Kieran.  I want to know what insects are mere transients through my garden, and which ones call my garden home.  I want to know which flowers the bees visit and which ones are merely eye-candy for me.  I want to see which ground beetles and springtails gather in my compost pile.  I'm curious to know if any insects dare tunnel through the hard, clay areas of unamended soil.

So far, I've collected 36 species of bee, 20 species of beetle, 29 species of fly, as well as springtails, snakeflies, mantids, and many other insect goodies.  It's amazing to me how hospitable a small patch of land can be, to so many different types of insects. 

Carol and her family are doing the same thing, although on a broader taxonomic scale.  And it all started with Carol's discovery of a rare moth on her Bellingham, WA windowsill ~ a moth that had, until that time, yet to be discovered (or at least, not recorded) in North America.  It made the Peterson - Yoon clan wonder what else might be discovered in their yard.  They thus set out to record every species they could catalog in their house and from their yard ~ efforts so elegantly reported by Carol in her New York Times article.

My own research has yielded a series of papers, co-authored with Kevin Matteson, Evelyn Fetridge and others, and suggests a few basic principles for insect biodiversity in gardens.

1. Gardens, even in the most heavily urbanized areas, host a diverse assemblage of beneficial insects.  (Fetridge et al., 2008; Matteson et al., 2008)
2. Plant more flowering plants, and you'll get more bees and butterflies.  The number of flowering plants in urban gardens predicted bee and butterfly diversity more than any other factor we measured. (Matteson and Langellotto, 2010).
3. Adding in native plants surely has benefits for wildlife (an argument convincingly made by Doug Tallamy in his book, Bringing Nature Home).  However, the small scale efforts often promoted by various organizations don't seem to have much of an effect, in terms of increasing beneficial insect diversity in gardens.  (Matteson and Langellotto, 2011). 

And, although I did not specifically research this principle, it should go without saying that if you want a diversity of insects in your backyard, you need to reduce or eliminate pesticide use ~ and in particular, reduce or eliminate use of broad spectrum insecticides.

In 20 or 30 years from now, it is my dream to publish a definitive list of the insects found in a single Oregon garden ~ all in an effort to show that gardens, if managed sustainably, really do offer promise as conservatories of insect biodiversity.

An Open Letter to Scotts Miracle Gro

Dear Scotts,

I was completely dismayed to read the recent announcement by the EPA that you were sentenced to pay $4.5 million in criminal penalties for illegally applying insecticides to wild bird food products, falsifying pesticide registration documents, distributing pesticides with misleading and unapproved labels, and distributing unregistered pesticides.

In a separate civil suit, you agreed to pay $6.0 million in civil penalties and spend an additional $2.0 million on environmental projects to resolve additional violations that include distributing or selling unregistered, canceled, or misbranded pesticides ~ including products with inadequate warnings or cautions.

You see, Scotts ~ my job is to coordinate the Oregon State University Extension Master Gardener Program.  I know you are familiar with Master Gardener Programs around the United States.  Over the years, you have supported many Master Gardener programs ~ including my own ~ with donations of funds or products.  I believe it was in 2009, Scotts, that you gave the Oregon Master Gardener Association (a non-profit organization that is separate from, but works to support the OSU Extension Master Gardener Program) $1,000 for the purchase of coffee and snacks at our annual conference.  Even though the donation was to the Oregon Master Gardener Association, I personally took a lot of heat from Master Gardeners who felt that accepting a donation from Scott's went against our commitment to sustainable gardening practices.

In answer to those many people who asked me 'why is Scotts sponsoring our coffee hours?', I reminded these concerned Master Gardeners that it is our responsibility to remain objective.  In response to the many, many times I've had Master Gardeners and others ask why we don't exclusively teach organic gardening practices, or why we don't confine our advice and recommendations to only include organic options, I've reminded them that whatever our personal opinions and biases might be, it is our job to remain objective.  Our responsibility is to educate clients about all of the options that are available to them ~ and then let clients choose the option that will work best for their gardening situation.  When working as Master Gardeners, we don't selectively choose among all possible options, to include only those options that we personally favor.

Our job is to educate, and not legislate.  We're descriptive, and not prescriptive. 

I've used these lines, many times, Scotts ~ when Master Gardeners have asked me if they could ignore that your products exist, or even make recommendations against your products.  Our job is to teach ~ and not to make decisions for others.

Oh, but Scotts, I'm now at a cross roads.  You see, in addition to the taglines 'educate, not legislate', and 'descriptive, not prescriptive', another mantra that we repeatedly teach in the Master Gardener Program is 'the label is the law'.  We repeatedly emphasize that the label on a pesticide container is a legal document, that describes legal uses for a pesticide.  In Oregon, Master Gardeners must spend at least 3 and as many as 10+ hours a year taking classes where we bring in our magnifying glasses and carefully read the label on a pesticide.  We talk about potential hazards of the product.  We talk about precautions we can take to reduce hazards to people, pets and the environment.  We talk about how it is illegal to exceed application rates, or to use a product in a way in which it is not intended.  We talk about active ingredients ~ those ingredients that are intended to specifically kill, deter or repel a pest ~ and how those active ingredients must be listed on the label.

And now, after reading about your recent violations of the Federal Insecticide, Fungicide, and Rodenticide (FIFRA) Act, and then doing some more reading to discover that these violations are not your first and that the violations extend to more than 100 of your products ~ my trust in your company and your products has been damaged.

When small, untested companies market products that are little more than 'snake oil' solutions, Master Gardeners are told that they can't include those products in the list of options that they give to clients.  Remember, 'research-based and reliable recommendations' is yet another Master Gardener tagline.

If your company has a history of:

• falsifying pesticide registration documents
• distributing pesticides with misleading and unapproved labels
• distributing unregistered pesticides.
• distributing or selling unregistered, canceled, or misbranded pesticides ~ including products with inadequate warnings or cautions.  

how can recommendations that may include one or more of your products be considered reliable?

I really want to know, Scotts.  How can we trust you after this egregious breech of the public's trust?  What should I tell the Master Gardeners that I teach?  What should I tell the clients who come to us for objective, reliable advice?

Until we can be sure that your products are reliable and legal, how can we in good conscience recommend them to our clients?

Sincerely,
Gail Langellotto
home gardener, and someone who works with many, many Master Gardeners and home gardeners