Important, must-read announcement regarding pesticide use

There’s a new report out from the Weed Science Society of America (WSSA) which blasts a common piece of gardening advice: use least toxic pesticides only as a last resort.  Popular as it may be, this advice is not scientifically grounded and can actually cause more harm than good.  The WSSA is joined in this announcement by the American Phytopathological Society (APS) and the Plant-Insect Ecosystems Section of the Entomological Society of
America (P-IE ESA).

This is a must-read for anyone who is a responsible educator regarding pesticide use, which includes Master Gardeners and other horticulture paraprofessionals.  You’ll want to use the webpage link above to read the entire announcement, but here’s a paragraph to get you thinking:

“There is no benefit or scientific basis to simplistic messages like “use least toxic pesticides as a last resort” for the large number of pesticide users who apply pesticides according to the label and practice good stewardship. Nor are these messages beneficial for those who neither seek training nor adequately read the label believing instead that it is safe, practical, and effective to simply choose a product considered a “least toxic pesticide” and apply it only as a “last resort.” These messages hinder pesticide safety and stewardship education and practices that are in the best interest of the pesticide user, our food supply, public health and ecosystem preservation.”

Up in smoke

If you read my postings the last few weeks, you know that I’m doing a webinar on Wednesday on searching academic databases for information of interest and use to gardeners.  While researching one of the suggested topics (should we mow leaves into the lawn or bag and dump them?) I found a 2012 article* entitled “Biomass yield from an urban landscape” in the journal Biomass and Bioenergy.  My blood ran cold when I read this part of the abstract:

“It was estimated that the City of Woodward could generate about 3750 Mg of biomass dry matter in a normal rainfall year and about 6100 Mg in a high rainfall year if every homeowner collected their lawn thatch and clippings, and tree leaves, twigs, and limbs for bioenergy production.”

My first thought was that is a botanical version of The Matrix.  My second thought was how misguided such a proposal would be.  Rather than using the organic material in our landscapes and gardens to replenish soil nutrients naturally, or greencycle it, we’d gather every shred and give it away to be burnt for energy production. Then we’d spend money on fertilizers (organic or otherwise, it doesn’t matter), many if not all of which require energy to manufacture, package, and/or distribute.

Does anyone else see something wrong with this picture?

I can tell you who wins with this approach, and it sure isn’t us or our gardens.

(*Springer, T.L. 2012. Biomass yield from an urban landscape. Biomass and Bioenergy 37: 82-87.)

A followup on the WOW post of last week

There was considerable interest in my post last week, where I shared a photo from Canadian garden writer David Hobson. I wasn’t impressed with the production method and materials for the petunia that was illustrated, but readers wanted to know a little more about the plant (how did the top of it look?) and the mesh encasing the root ball. So I contacted David, and he graciously shared some more information and photos with me.

Here are David’s comments:

“Attached are three photos. Not the best, but the one beside the broom is the original that I sent you. It’s been lying on the patio and has lost a few stems. I don’t have a shot of it in flower as I didn’t particularly like it — one of those new wine and yellow striped things. It was in a container with a couple of other plants and did flower somewhat, but not noticeably well.

“Next shot appears to be a coleus — slightly more roots, but hardly a star.

“Sadly, I can’t tell what number three is for sure as I retrieved it from the compost heap, but it has had an awful time trying to burst free with its tuberous roots.

“I do plant as many as 100 containers in all shapes and sizes each spring and all are all well tended, planted in my own compost mix, supplemented with water soluble fertilizer, watered as required, and suitably oriented.”Certainly, how well these plants thrive and produce blooms is an issue, but given the restrictive nature of this material, it does not appear to be at all biodegradable, a quality that one would think essential. After almost six months in soil, it has barely changed its structure.

“As an after note, I removed the fabric from the petunia and dried it. It is a very fine mesh. I then subjected it to a heat source whereupon and it shriveled and melted as one would expect a plastic material to perform — draw your own conclusions.”

The first photo is the petunia from last week’s post. I think it’s fair to say that the root system is significantly impaired and would require frequent watering to support the above-ground portion (which is pretty wimpy looking). The other photos show the same problems. And it’s apparent from David’s description that the plug wrap is probably made of a plastic of some sort.So, yes, I think it’s the production method – specifically the plastic mesh – that’s creating these poor quality root systems. Gardeners will have better luck with seedling liners filled with loose media.

Another WOW (why oh why) – “biodegradable” mesh for plugs

David Hobson, a garden columnist, sent me this great photo of his petunia planted earlier this year. Take a look at the root growth (or lack thereof):

I’m not sure where this particular product came from, but it looks a lot like a FERTISS propagation plug.  Here’s a description from their website of this product.”FERTISS is a ready-to-use, pre-filled propagation tray system. Cuttings are placed in a mixture of peat and perlite wrapped in a non-woven fabric. Roots of young plants will easily penetrate this fabric and enter the airspace between the fabric and the plastic cell wall. Roots are naturally air-pruned, resulting in a faster and better take, increased lateral branching, and improved transplanting performance.”

It sure doesn’t look like roots “easily penetrate” this fabric, at least when gardeners get them potted up at home.  And though I can’t see the top of the plant, I’m guessing it didn’t show “improved transplanting performance,” especially compared to a plug from a traditional liner pot.

Nowhere did I find what this “non-woven fabric” was made of (though there are allusions online to it being biodegradable), but it’s just one more impediment for plants – and gardeners – to deal with.

Plant sentience – a slippery slope

I maintain a “Garden Professors blog” group on Facebook, where people can pose questions and make suggestions. Ellyn Shea asked about the trend towards calling plants sentient, especially given the new book by Daniel Chamovitz – What a Plant Knows: A Field Guide to the Senses

Dr. Chamovitz is a respected scientist, and there is no doubt that plants sense and respond to their environment in ways we are still learning to understand. But couching plant responses in language associated with human sentience is a slippery slope.  Yes, it makes plant physiology more understandable to nonscientists, but it also leads to increased belief in pseudoscientific ideas. For example, here’s a response to an on-air interview with the author (the link is my own insertion):

“Over a hundred years ago Rudolf Steiner wrote about biodynamics and plant growth. Their sensitivities to the seasons, their environments, and humans…”

Here’s another:

“I have been talking to plants for years…our experimental garden overflows, the cellular intelligence, the capacity to communicate is deeply satisfying when you learn how to listen and feel what the plant is saying…they give us much information at a spiritual level as well as physical, i thank my flowers verbally, i sing to them,they respond in healing ways…water has the same living intelligence…talk to a glass of water with love before you drink it and it actually improves the feelings of health and flavor ….”

And another:

“One who understands this far more thoroughly than Chamovitch is Stephen Harrod Buhner, author of The Lost Language of Plants and the Secret Teachings of Plants, in which he details the most cutting edge cardio-neurological science which demonstrates that the heart (more neurons than muscle cells) is the body’s primary resonator and capable of direct energetic communication with the rest of the living community. All indigenous and ancient peoples knew this.”

Plant physiology is drastically different from animal physiology, and what we’ve learned about how plants work comes from centuries of careful scientific study – not from folklore and superstition.  For those of us Garden Professor types who spend time educating the public about plant sciences, anthropomorphizing plants or using imprecise language just makes our jobs more difficult.

A plant riddle for you

This week Jeff, Bert and I are brainstorming new and exciting ways that The Garden Professors can invade…I mean integrate into…the gardening world. (We’re channeling Holly, who had a conflict with another even this week.)  We’ll leave discussion of the particulars for another day.  But that’s my segue into my text-short but picture-perfect invasive plant story.

Earlier this spring I was in Palm Desert and spotted a large clumb of purple fountain grass (Pennisetum setaceum) in a landscape:

So here is the riddle: Why did the fountain grass cross the road?

To get to the other side.

Blue orchids?

I was at a big box home improvement store yesterday, and after doing my legitimate business I felt myself drawn to the garden center.  I smirked at the “drought tolerant cactus gardens” that had died from lack of water and the ever-popular GMO “cactus strawflower” (GMO = glue modified organism as illustrated in my January 13, 2010 post).  Then I spotted my prey du jour: a blue orchid!

A disclaimer on the tag warns that new blooms will be white:

Oh, and the source of the magic?  Check out the needle track and its gooey exudate:

Just say no to dye!

Are natives the answer? Revisited

I started to leave a comment on Linda’s Friday post regarding Seattle Public Utilities proposed building codes regarding “Healthy Landscapes” but decided I’d weigh in with a regular post.  Linda honed in on the 75% native requirement but there are lots of things to make one scratch their heads in the proposed codes.

Existing invasive plant species shall be removed and no invasive species planted.
No mention of how invasive plants shall be removed.  Heavy-duty herbicides? Armies of school children forced into slave labor? Slow-moving ground-fire? Goats?

75% of all new plantings will be native to Western Washington.
So where did 75% come from?  Sounds like a number that was pulled out of the air.  How is 75% defined?  75% of plants? 75% of the area?  And how does this foster “Healthy Landscapes”?  If I have a 2 acre landscape and plant an acre and half of salal or Oregon grape I’ve met the requirement of 75% but have I increased species diversity or structural diversity or contributed to a “Healthy Landscape”?

A vegetation plan must be submitted for review.
By whom?  What happens if they (whoever ‘they’ are) don’t like it?

Existing native plant species shall be protected whenever possible.
Sounds reasonable but what about existing non-invasive non-natives?  Could a homeowner be required to cut down a 40-year-old red maple?

And on and on we could go.  Let me state clearly, I’m not against native plants.  Quite the opposite – I grew up in western Washington and have a passion for PNW plants since my high school days.  Since moving to Michigan I’ve written articles and given talks promoting natives here as well.

Nonetheless, I think many in the native plant movement hurt their cause by parroting the same old lines without ever critically thinking about what they’re saying.  Repeating a lie often enough times does not make it the truth.

Let’s critically look at some of the reasons for planting natives according to the Washington State Native Plant Society:

Native plants are adapted to our climate of wet winters and dry summers.
True. But so are lots of non-natives.  Adaptedness is a function of the environment in which plants have evolved; whether it’s native or exotic.  There are many climates around the world that are similar to the PNW and can produce similarly adapted plants.

Require less water than most non-natives once they are established.
Once again, adaptations such as drought tolerance are a function of the climate under which plants evolved.  There are many exotic species that are more drought hardy than western Washington natives and likely to use less water.

Resist native pests and diseases better.
Sometimes. But unfortunately the days of worrying only about native pests are in the distant past.  Exotic pests are here and they are here to stay.  Dutch elm disease, white pine blister rust, emerald ash borer, chestnut blight, Japanese beetle, the list of exotic pests is long and getting longer.  Native does not mean pest-free.

Improve water quality by needing less fertilizer and no pesticides.
OK, here’s where I get confused.  The reasoning in Doug Tallamy’s book, Bringing Nature Home, is that native insects don’t feed on exotic plants, therefore if we plant exotics, native food pyramids will collapse and it will be the end of life as we know it.  So… if native insects won’t feed on exotic plants, why would exotics require more pesticide use?

Save resources and encourage a sense of Stewardship.
Ok, now maybe we’re getting somewhere.  Not sure why stewardship is capitalized here but if they mean a ‘sense of place’ or a ‘connection to the natural environment’ then I can buy it.  Many native activists, including Tallamy, run away from this argument – apparently it doesn’t sound scientific enough – but it’s one of the best we have.  Washington state has some of the most incredible plants anywhere.  They should be celebrated and promoted and planted.  In my mind, the biggest reason for planting natives – along with carefully selected non-natives – is to increase overall biodiversity.  When I mention biodiversity I am speaking broadly; species diversity, structural diversity, age-class diversity, and landscape diversity.  When we look to the future we have no idea what lies ahead. We don’t know what new, exotic diseases or insects are looming on the horizon. Most of us expect climate will change but no one can say with certainty how.  Plants cannot evolve as fast as climate will change or as fast as new pest will be introduced. The only way to deal with this uncertainly is to spread the risk through diversity – this includes natives, exotics, and even interspecific hybrids.

The natives debate continues…

Bert’s usually the one who posts on native plant news, but since he’s not in Seattle he will have missed this one.  So Bert, sit back and enjoy!

I just got an email from Seattle Public Utilities, who are having an open house to discuss “high efficiency landscapes” through their Green Code Provision Boards. One of the changes has to do with invasive species (a good thing). But these are the proposed changes:

Invasive Species and Native Vegetation (Regional Plan)

Who it Applies To:  For all new vegetated landscapes, or those being replaced


• Existing invasive plant species shall be removed and no invasive species planted.

• 75% of all new plantings will be native to Western Washington.

• A vegetation plan must be submitted for review.

• Existing native plant species shall be protected whenever possible.

I really don’t like the second bullet point.  75% natives?  Many of our Western Washington natives are understory plants adapted to the cool, moist coniferous forests that in no way resemble urban developments.   The few species that are able to tolerate hot, sunny, dry conditions won’t make for a very interesting or diverse palette. And we already know that a biologically diverse landscape is better than otherwise.

What’s wrong with using well-chosen nonnative plants that will tolerated urban conditions, support wildlife, and add some aesthetic interest?

Upside: he won’t have to mow for a while…

This is old news by now  – I’m surprised Jeff hasn’t pounced!!

Minnesota man accidentally kills entire lawn with herbicide

Sadly, the dead lawn ruined the plans for a charitable fund-raiser, also.

Lots of eye-rolling and sassy comments out there (from "duh" to "d’oh!") berating the guy
for not reading the label. Actually, my first reaction, too (RTFM, as
my Lt. Col. father would say.)

But it’s not so easy sometimes. I was trying to make out the fine print on the
silly peel-off, accordion-fold label on some Spinosad the other day and
it was impossible.  Finally gave up and looked up the application info on the interwebs. Not sure if that was the issue, but tiny, tiny print is a huge pet peeve of mine, so I’m comfy laying a bit of blame there.  

There is, however, readable print on the front label – the words "non-selective" and "glyphosate" and "grasses"  are large enough for even a blind squirrel like me to read. And I don’t know what on earth to think about the garden center employees who "helped" the poor guy.

(Another option: don’t get so worked up over weeds, says she with the
turf-like substance consisting entirely of anything but grass. But hey,
it’s green.)