Is there any future for a scientifically-sound gardening magazine?

(You’ll see two posts from me today.  This first one is easier to do at 6 a.m.)

One of the efforts I’ve been involved with is serving as science editor (and writer) for MasterGardener Magazine.  We started this quarterly publication in 2007 (take a look at it online at it here) – not just for Master Gardeners, but for anyone interested in sustainable gardens and landscapes.  Sadly, the publication went to an annual issue last year because of the economic downturn and now may be eliminated altogether.

Yes, this is a Washington state publication so when native plants discussed they are local natives.  But the information itself is applicable no matter where you live.  We had hoped at one time to offer regional issues, so that the magazine would have a local flavor.

Anyway, the publishers are no longer willing to carry a loss on the magazine.  What they really need are advertisers.

Any suggestions out there?  Most useful will be ideas that I can do from my computer or phone.

Pop Quiz!

Bet you weren’t expecting this on TUESDAY, eh?
Heh, heh.

Situation:  these photos are from a grad student project.  We wanted to create, observe, and record nutrient deficiency symptoms, so we grew the plants hydroponically in a made-from-scratch nutrient solution, containing everything except one particular nutrient. There were 12 separate batches of solution, one missing each essential mineral nutrient (N,P, K, Ca, Mg, S, Fe, Mn, Cu, B, Mo, Zn – couldn’t exclude Cl as it’s too common in salts).  As my research interest is herbaceous perennials, some common perennial taxa served as our victims, er, subjects.

Here’s the set up for the Verbena ‘Homestead Purple’ experiment – rooted cuttings were placed in the little buckets and secured by the lids. The nutrient solution was constantly aerated. For most elements, symptoms appeared between two and four weeks after the start of the project. Symptoms, depending on the elemental deficiency, included chlorosis (yellowing) of old or new leaves, leaf curl, speckling, stunted growth, and in one case, some excessive growth.

Below are results from day 42 of the study. We lifted the lids, hanging-basket style, so we could examine the roots. The control (received a complete nutrient solution) is on the left; Rapunzel there, on the right, lacked a nutrient. Quiz question:  What element was missing in this particular case?  What made you come to this conclusion?

Hint: If you have a rudimentary knowledge of garden fertility, be it veggie or ornamental, you can probably figure this out.  I’ll go ahead and rule out the pesky micronutrients.


(L) Control: received complete nutrient solution            (R) Deficiency solution

Are natives the answer?

Last week Jeff kicked off a lively discussion about invasive plants.  Let me state up front that no one on this blog is promoting invasive plants.  But the issues surrounding invasive plants are extremely complex and have profound implications for many groups with whom we work in landscape horticulture and urban and community forestry.  It is essential in these discussions that we separate fact from hyperbole.  In some quarters, lines have been blurred and people fail to make key distinctions and lump exotic, alien, or non-native species together with invasives.  According to the Federal Executive Order on Invasive species “Invasive species” means an alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health.  All invasives are alien but only a small fraction of alien species are invasive (all humans are mammals but not all mammals are humans).  Nevertheless, there is a temptation to ‘hedge all bets’ and promote only native species for horticultural planting since native plants, by definition, cannot be invasive.  In addition, there is a ‘feel good’ aura that surrounds native plants – if they’re native they must be good – that clouds some of the logic in the argument.

Some examples:

Natives are more stress tolerant and better adapted than exotics.
Really.  If native plants are always better adapted, why do we have invasives?  Shouldn’t the “better adapted” natives out-compete them? Stress tolerance and adaption are a function of natural selection pressures of the environment in which a species or population evolves.  The world is full of stressful environments and, therefore, lots of stress tolerant species.  There is no a priori reason, for example, to believe that a native species needs less water than an exotic.  The ability to withstand drought depends on the particular species in question.  I’ve done a lot of research on stress physiology of Scots pine – few, if any, native species here in Michigan can match it for drought and cold hardiness.  Moreover, as Jeff pointed out, most of our urban and suburban environments no longer reflect native conditions.  Urban heat islands can result in temperatures 10-20 deg. F warmer than the native countryside.  In our research on heat island effects in downtown Lincoln, NE we logged temperatures in tree canopies in excess of 125 deg. F.  These temperatures were coupled that with the usual urban conditions of impervious surfaces and compacted soils – what tree species is native to that ecosystem?

Native restoration?  This nurse-log ecosystem is typical of forests in western Oregon & Washington.  Trying to keep it alive in downtown Portland requires constant mist irrigation..

Native plants are more pest resistant than exotics.  This would be true if native pests were all we had to contend with.  But the exotic pest train has already left the station.  Emerald ash borer, Dutch elm disease, white pine blister rust, chestnut blight, Asian long horned beetle, and sirex wood wasp are here and here to stay.  And their friends are coming.  The continued expansion of global trade will almost undoubtedly mean that exotic pests, for which native trees have not evolved resistance, will become more, not less, of a problem in the future.   Relying exclusively on native trees means more, not fewer, catastrophic tree failures.  Heavy planting of green and white ash, which are both native in Michigan, has resulted in the loss of 30% or more of the urban tree canopy to EAB in some Michigan communities.

Natives increase diversity  This presupposes that exotic species do not or cannot fill niches occupied by natives.  Exotics can certainly add structural diversity and age class diversity to an urban and community forest.  I would also argue that they add to species biodiversity as well.  If we consider an urban community such as Lansing or Detroit, there are maybe six or seven native tree species that we could expect to have reasonable longevity as street trees.  If we expand our choices to include non-natives we can expand the list to twenty or so.  Not a huge number to be sure, but still a better hedge against catastrophic urban tree loss that the ‘native only’ policy.

Where to go from here?  We cannot ignore that fact the invasive plants are a huge economic and environmental issue.  Presently we do not have models that will accurately predict which exotics will become invasive and which ones won’t.  Trees that are demonstrated to be invasive in a given environment need to be dropped from planting programs.  Except for the desert Southwest and parts of the Plains, every region of the country has great native trees that can. and should, be an integral part of their urban and community forests.  While it’s tempting to play it safe and promote natives only, this policy has significant shortcomings.  Urban and community forests provide enormous economic, environmental, and societal benefits.  In order for our urban forests to provide these functions over the long term we need as broad an array of trees species as possible, including appropriate exotics.

Friday quiz

Thought we’d take a break from the invasive discussion (I have some throughts I’ll weigh in with on Mon.)  In the meantime, here’s a photo of dwarf Alberta spruce not too far from my boyhood home in Olympia, WA.  I get 2 or 3 of these calls each year; usually with a homehowner exclaiming, “I’ve got a tree growing out of my tree!”.

A thought about Invasive Plants

Recently there was an article published in the journal Science (widely considered one of the most prestigious science journals in the world) by two professors who I knew while I attended college in Pennsylvania (Franklin and Marshall College — Anyone ever heard of it?).  I found this article particularly interesting because it explained how the beautiful Pennsylvania scenery that we assume is natural was actually created over the course of three hundred years.  Saw mills and dams changed water flow patterns — those pretty streams that flow through the Southeastern PA (and nearby areas) that I grew up in aren’t natural at all.

Of course this is just another thing that we’ve done to make this country different from what it was when people first came here.  We’ve also farmed the heck out of the land, built large industrial areas and, on top of that, there’s the issue of global warming (which, for the sake of this post, we’ll assume is caused by humans), increased carbon dioxide in the air, decreased top soil and forest land (mostly because of the farming), and a general increase in soil, water and air pollutants.

So, with all that said, It seems to me that we’ve done a lot of things to change the environment.  With all that we’ve done why are we so upset when some plants, which we call “invasive” thrive in these settings?  It’s not their fault that they do well in the conditions we’ve created.  Sometimes I feel like we’ve built this great big smorgasbord of lutefisk (fish treated with lye — it’s pretty nasty) and then get angry when only people who grew up eating this type of fish come to the party.

I’m not trying to promote invasive plants — And I’ll be the first to admit that this post is oversimplifying the whole question of invasives — Still, it irks me sometimes that we aren’t more concerned about the environment where we plant our greenery rather than the plants themselves who, after all, are just feeding on the smorgasbord that we’ve created.

Veggie garden safety

A few months ago I posted a caution about using old pressure-treated timbers for vegetable gardens (see my Sept. 23 posting).  I now routinely get questions about alternatives to these arsenic-laden materials, especially new treated lumber.  What’s in the new wood that makes it rot resistant, and is it dangerous?

Rather than arsenic, new pressure-treated lumber has copper as its active ingredient.  Though it also will leach out of the wood, there is not a human health hazard associated with its uptake by plants or animals.  You probably get more copper leaching into the water carried through your plumbing (assuming you have copper, and not lead, pipes).

What about plastic timbers?  Though I’ve not seen any literature about leachates from plastic lumber, I’ve seen some older plastic timbers that haven’t aged well – they can warp and twist.  I would avoid those made of rubber, because decomposing rubber produces leachates that are quite hazardous (see September 30 for a discussion on rubber mulches).

Of course, there are many other materials one could use to corral their veggies – concrete blocks, stone, natural wood, etc.  Do you have a favorite?  Post a comment to let us know!