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For all of you getting ready to participate with us on Google + on Thursday I need to get you into our circle, so if you could either search for me on Google + and friend me, or, alternatively, e-mail me (gillm003@umn.edu) and let me know you want to participate, that will be necessary for your participation.

We are planning to record this session and make it available on you-tube (assuming I can figure out all the technology).

I have been told by a few people that my scheduling stinks because many of you work.  I hear you loud and clear!  Next time we’ll try to do this in the eveni

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:

Are natives the answer?

Controlling invasives with schoolchildren

Controlling invasives with goats

Over the past week the garden professors have been playing with something new, and we think it’s time to try it live with all of you.

Hopefully some of you are aware of Google and Google +.  On Google + there is a feature called “Hangouts” which lets you interact directly with up to ten people at once using camera and microphone.  More than that can participate by watching the discussion (though I’m still working that out on my computer — it should be ready by the time we go live.)

Next Thursday August 30 at 11:20 Eastern, 10:20 Central, 9:20 Mountain, and 8:20 Pacific time we’re going to start a hangout on Google + and invite all of you to join.  Then we’re going to start a live discussion.

The topic of the discussion is related to, but not exactly the same as, Bert’s somewhat controversial post from last week — “Should the government be able to require you to plant natives on your own land.”

As a side note, if you want to read how the Florida Native Plant Society responded to that post please read this.  Wow!  Even though the topic we’ll be discussing doesn’t deal with Bert’s post directly, hopefully someone (or a few people) from the FNPS will join us.  I’ll drop a comment onto their blog to make sure they at least know about the opportunity.

We are open to tangents in the discussion.  We want this to be open ended, fun, and informative.

So what do you need to do if you want to participate?  For right now the thing to do would be to get a google + account.  Just go here.  Also, if you don’t have a camera or microphone hooked up to your computer — now would be a good time to do that.  We’d also appreciate it if you’d comment on this post to let us know that you are planning on participating (or want to participate but can’t make it).  Please keep in mind that if we don’t have much participation we probably won’t try this again — at least not for awhile.

We’ll provide more instructions and information on the blog as we get closer to next Thursday.  We’re looking forward to this and hope that many of you can join us.

It recently came to my attention that the Sierra Club published an article on a new system for reducing watering in lawns.  You can read it here.  Basically what the company, AquaCents, does is inject a polyacrylamide gel into the landscape and then the gel supposedly collects irrigation and/or rain water and releases it for plants to take up as the landscape dries.

I think it’s a good concept, but I’m highly skeptical that this is a good product for two reasons.  The first is that I’ve used polyacrylamide gels to hold water for plants before and have found no benefit.  In fact, most papers out there on the topic show either no benefit or marginal benefit from using these gels in terms of increasing the amount of water available to plants – though I must admit that results are variable.

Please note that I didn’t say I was skeptical that the polymer will hold lots of water – I’m not.  It will hold lots of water.

Which leads us to an important question.  If we know that the gel will hold water, and this company has done testing which shows reduced watering is required in lawns that use this technology, then why am I skeptical?

Based on what I have read and the experiments I’ve done, I think the company’s testing isn’t telling the whole story.

As far as I can tell, what they’re doing to test this product is injecting it into lawns and then allowing a moisture detector in the lawn to trigger sprinklers to go on when soil moisture falls below a certain level.  If you test one lawn with the polymer side by side against another lawn without the polymer, then the lawn with the polymer will use less sprinkler water because the gel holds more water than the surrounding soil – meaning that it stays more moist. So at this point it sure seems like the gel is a good idea — right?

No, because this experiment asked the wrong question.  It looked at how much water was in the lawn, NOT HOW MUCH WATER WAS GETTING TO THE PLANT.  And that’s what we need to know – how much water gathered up in that gel will actually get to the plant.  What I’ve found in my work is that having water in the gel is not the same as getting water to the plant.  The gel seems to hold the water too tightly for the plant to get it.  It’s a little like having an impenetrable safe filled with five million dollars in gold.  Sure, the gold is there, but if you can’t get to it, who cares?

So, why does the grass seem to be growing more roots when the gel is used?  My best guess is that the lawns were overwatered in the first place and the gel just provided a way for homeowners to decrease their watering.  Let’s face the facts, overwatering of lawns is rampant.

But I mentioned that there were two reasons why I didn’t like the gel.  I named the first, so what’s the second?  It’s something that I saw on one of Linda’s sites a few years ago and then looked into a little further.  Polyacrylamide gel, while relatively safe in and of itself, may break down into more toxic substances.  See Linda’s article here.

Finally – and this is just a thought — there are plenty of other absorbent materials out there that might be injected into the ground, including some made of starch – I have tried gels made of starch and have found them to be as effective as those made of polyacrylamide (though I know that’s not saying a lot).  Or…maybe we should just water more judiciously.  Like I said, just a thought.

I recently spotted this in the window of a toy shop:

Recommended for ages 10 and up. My youth was apparently misspent with Hot Wheels and model horses (and collisions thereof).  I could have been getting a step up on grad school.

"See genetic material with your
own eyes as you isolate the DNA from a tomato in a test tube." (This is actually fun and easy and you don’t need a kit to do it.)

"Learn about dominant and recessive genes and play inheritance
games to determine how traits will be expressed."  Then you can blame the correct parent for your near-sightedness, flat feet, etc.

"Breed your own bacteria colony to experiment with survival of
the fittest."  Now, we’re talking!!!  I would have loved this.  My mother, however, would have argued that the disgusting storage space under my bed was, in fact, a giant petri dish.

Just flew in from Miami and boy are my arms tired – rim shot.  Seriously, I just returned for the annual meeting of the American Society for Horticultural Science (ASHS) in Miami.  Always good to wander the halls and renew old acquaintances and take in the latest in Hort science.  Judging by the posters and talks here are some of the hot topics at this year’s ASHS meeting.

LED’s
Horticultural applications of Light Emitting Diodes (LED) are receiving a lot of attention these days.  There are a couple of reasons for this. One, costs of LEDs are decreasing as manufacturing becomes more efficient.  Two, LED’s can be built to generate specific wavelengths of lights.  As many folks learned in biology, plants only use specific wavelengths during photosynthesis.  Therefore LED’s can be used to only produce the light energy that plants need for photosynthesis – this can greatly increase energy efficiency.  Aslo, incandescent light bulbs are being phased out of production.  Old fashioned bulbs are not very efficient (they yield about 10% of energy used as light) but the light they do produce is effective for things like phot- period lighting (i.e., daylight extension for greenhouse crops).  Since LED’s can be designed to reproduce the same wavelengths using much less energy, they may ultimately be a good substitute for incandescent bulbs.

High tunnels

Lots of interest these days in ‘high tunnels’ for fruit and vegetable production.  These are not full-blown greenhouses but simply tall hoop-house structures big enough to grow fruit trees inside.  One of the main benefits is season extension; allowing fruit or vegetable harvests earlier or later in the season than would be possible otherwise.  This is especially important when we consider the local food movement for colder climates.  There are also other, less obvious, benefits such as eliminating cracking of cherries due to rainfall.

Sensor-based irrigation systems

A hot topic, especially for the nursery crowd.  There have been rapid advances in the reliability of capacitance probes and while costs are decreasing.  In addition, there have been advances in wireless control systems.  There are still challenges for nursery growers that have to deal with a diverse array of crop types and container sizes but researchers are definitely on the path of developing sensor-based systems that will automatically turn irrigation on and off in response to real-time soil moisture measurements.  This will help to optimize plant growth while minimizing potential leaching of nutrients and chemicals.   

One of the recommendations that I always make when I discuss organic methods that work is bagging fruit.  If you’ve never heard of it then here’s the story.  By placing a bag of some sort around your fruit, such as apples or peaches, when they’re young you can protect them from insects and disease.  I used to recommend plastic ziplock bags (up here in the North anyway), and I still do, they’re cheap and work well.  You can also purchase Japanese fruit bags that will work.  But recently I was introduced to a more streamlined product which I really like — a cloth pocket with a cord to close off the top.  Since it’s made out of cloth it probably won’t protect against disease as well as plastic bags or Japanese fruit bags, but if insects are your main concern then I think these might be just perfect for you — if you don’t mind paying a few dollars for them (they are reusable!)

At a master gardener conference I recently attended one of the vendors handed me some of her Startbagging fruit bags to test on tomatoes.  I say test because, while these bags have been pretty effective at protecting tree fruits, they haven’t been used much for veggies (OK, OK, a tomato is technically a fruit).  To be honest though, I’m not as worried about insects on tomatoes as I am deer.  The deer near me don’t seem to care for the plants themselves, but they just love to pick the tomatoes off when they’re almost, but not quite ripe.  Jerks. 

Here are a few bags on a tomato plant.

Here’s a closeup of one of the bags.

I’ve only had these bags on the plant for about a week now — so far so good.  The company producing these bags is a small start-up.  From what I understand these bags are patent pending.  I wish this company well because I think this is organic pest control at its best — reusable products that don’t utilize chemicals.  If you have any interest you can go to startbagging.com to take a look (the website is a little basic right now — hopefully they’ll fix that soon!).

Just a little bit of show and tell today.  The week before last the Central Region of the American Conifer Society (ACS) hosted the National ACS meeting here in Michigan.  Over 300 conferites gathered to discuss their favorite plants and share their conifer addiction.

The highlight of the meeting was a field trip to the Harper Collection of Rare and Dwarf Conifers at Michigan State University’s Hidden Lake Gardens.  The Harper collection, which was donated to MSU by noted plantsman Justin ‘Chub’ Harper is a world-class assemblage of conifers and includes over 550 plants displayed in a wonderfully-designed layout.

To add a little fun to the outing, each ACS member was give three pink pin-flags and asked to mark their three favorite conifers.  Tough to choose just three from this collection. 

ACS members descend on the Harper Collection

Adrian Bloom adds his vote to Metasequoia glytostraboides ‘Gold rush’

The elephant tree. Pinus strobus ‘Pendula’

Got my vote but wasn’t the winner: Taxodium distichum ‘Pendens’.  If the meeting had been in October when this tree is in fall color, this would have won hands down.

And the winner is… Abies concolor ‘Blue cloak’

Linda’s posting this week made me nostalgic for some good old garden guru advice, so I couldn’t help but zip on over to Jerry Baker’s web site (www.jerrybaker.net) to see if he had anything interesting to tell me.  I wasn’t disappointed!  Here is one of his recommendations:

Three-minute eggshells

“Place eggshells in the microwave for three minutes, remove, crush into a fine powder, and place them in a cloth sachet. Then drop the sachet into your houseplant watering can to give your indoor plants a nice nitrogen-boost.”

Wow! how about that! Eggshells for a nitrogen boost!  Who woulda thought….  Anyway, after I saw this, I got to thinking, maybe, just maybe, there might be some nitrogen there…..

So I microwaved four eggshells, crushed them, and put them into a half-liter of water, then let them sit in the water for about 9 hours.  Then I filtered the water off and ran that water (along with a control sample) over to our soils lab to be tested.

And wouldn’t you know it?  That water DID have nitrogen in it!  About 5 parts per million!  Which is about 1/10th of what I would consider even close to a fertilizer application….So then if we do the math, that would mean that eighty egg shells per liter (about a quart) would make a decent shot of nitrogen.

Sorry Mr. Baker, I just don’t eat that many eggs.

In prepping grad students for their first big talk at a scientific meeting I always tell them everything will be fine – until the first data slide hits the screen.  The audience will nod knowingly during the introductory comments and even during the materials and methods, but data charts and tables are to scientists what chum is to hungry sharks.  So clearly I should have known better than to post figures without error bars in last week’s post.  In my defense, SigmaPlot, my program of choice for scientific graphing, currently resides on my old laptop which is running slower than molasses, so I did the ‘quick and dirty’ and used PowerPoint on my desktop.  Yes, my mother did raise me better than the present a measure of central tendency without an indication of dispersion.

So, duly chastised and humbled, I present the latest (July 12) volumetric soil moisture values from the SoMeDedTREEs.  N=8 for all means *=means are different at p=0.05.  The table below is more complete than last week’s post, which only presented the means from measurements just outside the container root ball.

Mean (std err) volumetric soil moisture of planetrees at MSU Hort farm, with and without 3” of ground red pine mulch

Inside container ball			MC%	std. err.
	15 cm	Mulch*	10.7	1.9
		No	6.4	0.6
	45 cm	Mulch	10.6	1.5
		No	10.5	1.7
Outside ball
	15 cm	Mulch*	21.9	1.3
		No	16.7	0.7
	45 cm	Mulch*	26.1	0.9
		No	23.1	0.9