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.)

For “entertainment value” only

So reads the sticky note from my retired entomologist colleague.  It’s affixed to the latest flyer promising the "greenest garden in town" using the "best all-time tips, tricks and tonics."

The entire brochure is ludicrous, and picking it apart is like shooting fish in a barrel. But sometimes it’s fun going for the low-hanging fruit. Here are some of the more memorable claims:

Epsom salts – grow sweeter melons, energize your roses, supercharge your grass seed, grow giant geraniums, bust tomato blight, boost your bulbs, force stubborn shrubs to flower, etc. etc. How does plain old magnesium sulfate do all of these miraculous things? The short answer – it doesn’t. There’s not one speck of science behind any of this nonsense. (On a more amusing note, the garden guru’s chemistry is a little shaky.  He claims Epsom salts will "give bulbs a dose of much-needed nitrogen." Either that or he’s figured out alchemistic transmutation.)

Barbeque forks – "perfect for spot aeration, harvesting root crops, and mole control." Eeew.

Latex paint – "seal up fresh cuts on trees, shrubs and roses." A colorful way to inhibit a plant’s natural ability to seal wounds.

"Stress reliever tonic" for lawns that contains shampoo, tea, mouthwash, and "chewing tobacco juice." Not only is this a toxic mess, but how is one expected to produce the "chewing tobacco juice?"

Salt – it’s not just for slugs anymore!  You can use it on weeds, "bad" worms, poison ivy, and ants.  Somehow the "good" plants and insects are immune to the effects? 

According to the back of the brochure, our guru has "taught" over 32.7 million people how to misuse common household products in their garden.  Incredible.

Suddenly Symphyotrichum

Also the Anemone x hybrida, Solidago, etc.  Everything’s blooming early here in the Mid-Atlantic.

"Fall-Blooming Anemone." Not.

I teach an herbaceous plant i.d. and use course each fall and spring. By looking back at my plant lists, I can tell what was blooming when.  I usually teach the asters at the end of September.

That’s going to be tough this year, since they are all BLOOMING RIGHT NOW dammit.   This will be a great experiment in "does deadheading = rebloom" for many of the asters.  Things like garden phlox (Phlox paniculata) are dependable post-deadheading rebloomers, but I can’t say I’ve ever  needed to deadhead Asters to get another flush of blooms, since they bloom right before frost for us, then pffftttt anyway.

Great Fanny’s Aster, this is too early! (Sympyotrichum oblongifolium ‘Fanny’)

My source for perennial maintenance advice is Tracy DiSabato-Aust’s marvelous "The Well-Tended Perennial Garden."  I’ve utilized her strategies for cutting back to both delay blooms and create a more compact plant.  If I’d been thinking ahead (ha, ha!), a good whacking on some of these things might have fended off blooms for another month or so; or at least had something to look at when class starts at the end of August. But alas. At this point the best I can hope for is a sporadic bloom or two.  At least I have lots of photos for lecture…

The ugly side of compost

In my part of the world we’re able to send most of our organic stuff through the green cycling program, where it ends up being made into compost.  Cedar Grove contracts with the City of Seattle to do this service.  As you might imagine, this requires huge, multiple facilities to handle all of the organic material that comes through the system.  And it’s not difficult to imagine that problems arise, especially in choosing locations for these sites.

I don’t know anyone who would welcome a large composting facility next to their neighborhood, and I sympathize with people who were living downwind of where these facilities were constructed.  (People who moved there afterwards should have known what they were getting into.)  But even worse is putting a facility in an environmentally sensitive area – like on an island.

On one hand, it might seem the perfect solution – put the facility on an uninhabited island to keep mainland neighbors happy.  On the other hand, it’s an ISLAND – runoff is going to be a problem.  So if such a site is chosen, then the company should be required to manage runoff and keep it out of the water.

Thus, I was most severely vexed to hear that Cedar Grove has asked to be exempted from the rules regulating phosphorus runoff into the adjacent slough. Unlimited amounts of phosphorus.  The facility routinely exceeds the legal limit of runoff of phosphorus and occasionally other nutrients set by the state Department of Ecology. Citations, fines, and out of court settlements are nothing new to this company.

According to their spokesperson, Cedar Grove "cannot find a treatment that would work" to manage phosphorus pollution and need a waiver from the requirements. Somehow this has become the public’s problem and we should just absolve Cedar Grove of any responsibility to be a good environmental steward.  

I don’t know what bugs me more: the fact that this corporation did not design an adequate facility to contain the runoff before it began operations, or that whatever governmental agency approved their plan didn’t require it.

Shut ’em down.

MossTiles – a really bad idea

A few months ago a colleague alerted me to MossTiles, which can be attached to walls to create interior vertical gardens. They look really cool, and I assumed they consisted of some tough little moss species rooted in a mesh-enclosed planting mix. But the more I read about them, the more confused I became. They don’t need light – or fertilizer – or water (though misting them occasionally is recommended). More investigation was in order.

It turns out that these aren’t made from moss at all, but lichens – specifically reindeer moss (Cladonia rangiferina). This slow-growing lichen is harvested in Scandinavia, "stabilized" in a salt solution, glued onto tiles with a resin, then dyed one of twelve different colors.

Come on. This isn’t a plant anymore. It might as well be made out of plastic. All the misting does is keeping them from drying out and crumbling to pieces.

Even worse, reindeer moss is a major food source for caribou and other large ruminants. It’s so slow growing that it’s a threatened (and protected) species in some parts of the world. Do we really need to have preserved plants hanging on our walls like some kind of botanical trophy?

If so, be sure you’ve got a fat wallet. Installation of MossTiles costs about $200 per tile.

Why I don’t like cardboard mulch

I’ve discussed my dislike of cardboard mulch before: like other sheet mulches it restricts water and gas transfer between the soil and atmosphere. In published comparison studies, other mulch choices generally outperform cardboard in terms of plant growth, weed control, etc. But there’s one area where cardboard is tops compared to every other mulch material tested.



Termites LOVE cardboard. Did you know that termite researchers use cardboard feeding stations to lure termites? And cardboard is often used as the “control” in feeding studies, because termites will always eat it?

People seem to think that wood chips are termite magnets. Though termites can eat some types of wood, they prefer cardboard in taste testing. If they are given no choice and have only wood to eat, they will consume it but their survival rate decreases. Dead termites don’t reproduce.

To give termites a bit of a break, they are very useful in bringing life back to crusted, arid soils: studies have shown that just adding mulch and termites to these degraded soils is enough get biological processes going again.

But personally, I’m not providing a cardboard welcome mat for termites to the gardens surrounding my wooden house.  Hopefully you won’t either.

Of Football and Forests

 Howdy all – I’ve been on vacation and then inundated by all that accumulates whilst on said holiday. Here’s a whopper of a belated post. What follows is an account of events you may find interesting (or amusing, or frustrating).

Here’s a portion of a recent press release from the media office at Virginia Tech, regarding our making the "Green Honor Roll."

BLACKSBURG, Va., April 25, 2012 – For the third consecutive year, Virginia Tech ranks among the most environmentally responsible colleges in the United States and Canada, according to the Princeton Review, receiving the highest possible score given by the organization.

The Princeton Review’s Guide to 322 Green Colleges: 2012 Edition, released April 17, profiles institutions of higher education that demonstrate a notable commitment to sustainability in their academic offerings, campus infrastructure, activities, and career preparation. The Princeton Review, in collaboration with the Center for Green Schools at the U.S. Green Building Council, evaluates colleges and universities and assigns a numerical score on a scale of 60 to 99. 

Virginia Tech received a score of 99, earning the distinction as one of 16 colleges to be named to the Princeton Review’s 2012 Green Rating Honor Roll

“Virginia Tech continues to be totally committed to campus sustainability," said Denny Cochrane, Virginia Tech’s sustainability program manager. "Our inclusion on the Green Rating Honor Roll shows how wide spread the commitment is among out students, faculty, staff, alumni, and university leadership."


The story of “Stadium Woods” is interesting and complex.  Virginia Tech Athletics announced the construction of an indoor practice facility for football on part of an 11-acre wooded site, behind Lane Stadium and abutting the current practice field (hence “stadium woods”).  The campus Landscape Architect brought it up at a meeting with the campus Arboretum Committee, who were not thrilled. Virginia Tech has followed a plan of very concentrated/intense land use to keep everything within walking/running distance for the students, and this was one of the few wooded areas left.

The committee proposed an alternative site a few hundred yards away, with the new facility replacing some tennis courts and a roller-hockey rink. 

This suggestion was not met with great enthusiasm by the Athletics department.

Two possible sites for indoor practice facility, adjacent to practice field where 200-300 year old trees are, or along Washington Street on top of some tennis courts (also possibly 200 years old).

At that point, an immense hoo-ha began that would stretch over a year.  I’m going to leave out the ensuing committee/administrator/athletics blow-by-blow, but in a nutshell, some of the Forestry faculty determined this was not just “woods” but a rare stand of old-growth forest, and the Athletics folks were insistent “this is absolutely the best place for the facility!”   Football is huge at Virginia Tech, thus anything described as giving an edge in recruiting gets maximum priority.  In the event of a thunderstorm, having the student-athletes run an additional 150 yards from the practice field to the alternative indoor facility location was just not acceptable. Other issues included digging up a ton of infrastructure (steam lines, electric, etc.) that runs along the road, plus the height of the proposed building does not conform to the campus Master Plan (since it’s for football, it has to be be tall enough to kick a field goal in. We really do need a lot of practice at that.) Guesstimates are around $1million increase to account for the infrastructure issue (added to the $15 million estimate for construction).

A community group “Save Stadium Woods” was formed, complete with a (very nice) website and a letter-writing campaign to the local newspaper. There were petitions, resolutions from everybody and their mother, and more.  The local coverage was intense plus there was a letter to the editor in nearly every newspaper issue for the past three months. CNN even covered the story, which was great, as no campus shootings were involved for the first time in a
while.  One of the 300+ year old white oaks was named “Stephen Colbert” in an effort to raise awareness (?!?).  

An ad-hoc committee of university administrators, both Athletics and non-, plus interested parties from both the faculty and the community was charged by the President to come up with a solution. 

And of course, a third-party consultant was brought in, because we apparently don’t have enough smart people here on campus.

Yes, quite the head-scratcher… place the building and site footprint on top of 3 acres of steeply-sloped, old-growth forest? Or remove some aging and underused tennis courts, which could be relocated to the intramural athletics area on the fringe of campus. Yet Athletics continued to argue, and University administration was silent.

The committee weighed in a week ago, coming to the logical conclusion of protecting the woods and utilizing the tennis court site.  I guess the weirdest part of this is that something so no-brainer-ish was allowed to drag on and on, giving our beloved Virginia Tech and so-called “Green University” (complete with TreeCampus USA designation) a black eye. 

The Pop-n-Drop method of planting shrubs

One of the planting practices that severely vexes me is the Pop-n-Drop (TM) method, where plants are popped out of the container and dropped into a hole roughly the same size.  When I’m lucky enough to find such installations in progress, I try to take as many photos as possible for later comparisons.  Here’s one such landscape that was installed in this manner:

A row of Pop-n-Drops in 2002

And here’s the same landscape 10 years later:

Two rows of Pop-n-Drops in 2012

Some of the shrubs survived, some did not, and certainly none of them are thriving.  You can see that the shrubs have remained about the same height after a decade of “growth.” Yet this practice continues to be SOP for many landscaping companies all in the name of shaving off a few minutes of labor and making a few more $$.

We GPs can (and do!) disagree about how much root preparation is needed before planting containerized and B&B trees and shrubs.  But I don’t think any of us would recommend NO root preparation.

(Additional note:  the “before” photo is the side of the landscape that faces west.  Those shrubs are gone.  The “after” photo is facing south (this is a corner lot).  All of the landscapes were put in at the same time, in the same fashion.  Unfortunately I didn’t take photos of the south facing landscape when it was put in, and the one that failed on the west was replaced before I knew it had died.  Sorry for not including this explanation initially.)

And here is the 2012 landscape from a closer viewpoint; note the dead shrub on the left end of the lower row.  The others are all failing, in both this row and the upper row: