Monthly Archives: June 2011

What Happens to the Horticulturist?

A couple of weeks ago I had the opportunity to talk with a professor in the agronomy department who’s going to be retiring very soon.  We talked about education and field trials, corn and trees, and then we started talking about the future of our departments.  Both of us are concerned that this generation of horticulturists (and agronomists—but I’m just going to deal with horticulture here) will be the last. 

Over the last 10 or so years we have been losing horticulture departments.  Because of smaller budgets colleges and universities have combined hort departments with other departments to save money.  But I don’t see this as a major problem, after all, a rose by any other name would smell as sweet (OK – truth is I don’t know many sweet smelling horticulturists).  Horticulturists can be in departments besides horticulture and still do their job…But what is the job of a horticulturist at a university?

There will be all kinds of opinions on the “real” job of a horticulturist, but I believe that a big part of being a horticulturist is being a generalist – knowing a little about a lot of different things – insects, plant disease, soil.  We’re a little like a general practitioner who can take care of basic stuff and then refer the client to a specialist if needed.  Though most of us work with a particular type of crop (historically horticulture was split into 4 large groups – floriculture, fruit, vegetables, and landscape horticulture), horticulturists generally know enough about other crops so as not to make too much of a fool of themselves if they talk in general terms.  We know how plants work, and we know how the environments around them work to help them grow.  We are, in many ways, applied ecologists who are concerned about landscapes and the production of what many consider “minor” crops (at least compared to corn and soybeans!).

The biggest problem, as I see it, is that we are not hiring, or training, the number of horticulturists we once did.  In colleges and universities a premium is placed upon hiring faculty members who can acquire big dollars through federal grants.  The government likes “sexy” research which, right now, includes things like genetic engineering and biochemistry.  The government is open to having this work done on crops like apples and onions, or even nursery stock.  The problem is that generalists don’t tend to have the specialized knowledge in genetic engineering or biochemistry to do the work.  Hence, a biochemist or molecular biologist is hired and, hopefully, gets the grants the university needs.  But, in my experience, rarely do they really understand the crops they’re working on in terms of actually growing it.  Some do of course, but in the cases where they do it tends to be after the fact – in other words they learn about the crops after they begin working on them and their knowledge is often very basic.  I suppose this is OK, but to me it is sad that we’re not hiring what I consider true horticulturists anymore.  And, because we’re not hiring true horticulture faculty we’re not graduating many horticulturists from our graduate schools either.  Sure, we’re graduating molecular biologists and biochemists – and even a few breeders (who very often are horticulturists) – but these students may or may not leave a university with knowledge of “horticulture” as a whole.  And if we don’t start hiring more horticulturists what will happen?  Who will teach our introduction to horticulture course – or will horticulture just fragment and we’ll all need to go looking to specialists.  I don’t know, but it bothers me.

A Garden Professor migrates east, albeit briefly

I was AWOL last week, as I had 3 presentations to get ready for 3 different states all in the span of 4 days.  Yow!  But they are over and done, and I’ll try to keep up on the blog from now on.

This is a short but amusing post (to me anyway).  My second talk was in Virginia, where I spoke to Master Gardeners at their annual conference.  The speaker right before my talk was fellow GP Holly Scoggins.  (Note to self: never agree to follow Dr. Scoggins again.  I’m not nearly as amusing, though I am almost as tall.)

Anyway, Holly was discussing garden trends among other things and mentioned meta-gardens.  Hmmm.  I hadn’t heard of these, but assumed that, like meta-analyses, they were probably gardens that showcased plant collections from other places.  Kind of like arboreta but smaller, and maybe something you could do at home.  I nodded wisely, pretending that I was fully on board with this new trend.

Alas.  My west coast ears were not adapted to Holly’s southern accent.  As I discovered several slides later when it was obvious she was talking about meadow gardens.

Oh well.

Does native matter?

We’ve had lots of lively discussion on my post regarding the Mark Davis et al. comment in Nature on natives and exotics.  I have been traveling and otherwise occupied and have not had a chance to comment so I feel a little like the kid that kicked the anthill and then ran away.  Fortunately, Holly was gracious enough to forego her post today (I promise to return the favor, Holly!) so I can chime back in.

Obviously there are lots of layers to the debate but one of the main items in the discussion is whether there is an inherent ecological advantage in planting natives over exotics.  At this point the focus always seems to shift to herbivory and the question of whether native insects will eat non-native plants.  There are certainly examples each way; some insects are generalists while others are highly specific.  More importantly, however, plants fill many other roles in the environment beyond serving as food for insects.   Moreover, species composition is just one aspect of diversity.  The ecological function of landscape is also determined by how we manage other factors such as structural diversity and age class distributions.  In his book “Bringing Nature Home” Doug Tallamy shows a picture of a bland, sprawling suburban landscape ( p. 24) and notes “this highly simplified community is made up of a few species of alien ornamental plants that provide neither food nor shelter for wildlife.”  OK, I’ll buy that.  But would the situation change if the blue grass was changed to a native grass kept mowed to 2 ½” and the two widely spaced shade trees were changed to natives?  Doubtful.   The structural complexity; that is, the number and arrangement of grasses, annuals, shrubs, and trees, is likely a bigger driver of ecosystem function than whether the plants are native or exotic.

In his thoughtful comments on the blog post Vincent Vizachero sums up, “I stand by my view that the general heuristic of favoring native plants over alien plants is better than the alternative of not caring about origin at all.”   I can buy that as well, but with the caveat that other factors are equal.  The rub, of course, is that other factors are rarely equal.  And I suppose this is where the pragmatic approach discussed by Davis et al.  resonates with me.  In my position I do a lot of programming on trees for urban and community forests.  I go through a list of criteria to consider for tree selection.  Here are some of the key factors I usually discuss:

Adaptation There is no argument that there are well-documented environmental, economic and social benefits to trees in urban and suburban areas.   But in order to fulfill these roles trees must be able to survive where they are planted.  This means being adapted to abiotic and biotic environmental conditions which are often adverse.  In this region of the country there are some native trees that fit the ‘tough trees for tough places’ bill, such as swamp white oak, bur oak, and honey locust.  Many other natives, especially understory species, are much more difficult to site.

This street planting in Lansing alternated green ash and Norway maple.  

Available space This seems like a no-brainer, but it’s amazing how often this gets overlooked and we end up with too much tree and too little space.  Again, we have some great small native trees; Carpinus, redbud, striped maple.  But these can be limited in their site adaptability.

Ash stumps

Diversity  In Michigan some communities have lost 30% of their tree cover to the emerald ash borer.  Have we learned our lesson about improving species diversity?  Not really.  But we need to keep trying.  Exotic pests are here and here to stay.  Does anyone believe that global trade will decrease in the near future?  Does anyone believe that there will be quantum leap in our ability to detect and intercept hitch-hiking pests?  In order to continue to accrue the benefits of urban and community forests we need to continue to diversify our portfolio; this includes a mix of natives and exotics.  I doubt there will ever be sufficient data to prove one way other, but it seems reasonable to me that an urban and community forest balanced among 20-25 native and exotic species will be better able to withstand the slings and arrows of weather and pests better than one made up of 8-10 natives.


Imprelis damage to landscape conifers

Herbicide issues seem to be dominating my life these days.  Over the past several weeks reports have surfaced around the Midwest of landscape conifers – primarily spruces and pines – that have developed rapid and severe die-back.  While there are a host of insect pests and pathogens that can cause die-back in conifers, the recent cases are noteworthy in the speed with which trees expressed symptoms.  

Photos: Andy and Carol Duvall

In many cases that have been reported the common thread appears to be the use of Imprelis, a turf herbicide developed and marketed by Dupont.  Imprelis (active ingredient: aminocyclopyrachlor) is a synthetic auxin designed to control broadleaved weeds in turf.  Ostensibly, one of the advantages of Imprelis is that has root activity in addition to foliar activity.  It appears, however, that it may have too much root activity and the internet is abuzz with photos and posts of Imprelis-damaged conifers.

So what’s going on?  Well there are lots of blurbs coming out and lots of things being reported second and third-hand.  I suspect a few things we ‘know’ about Imprelis right now will turn out not to be the case in a few months.  Dupont has tried to shift blame to the applicators, suggesting that their rates may have been off, they applied when there was potential for drift, or that the material was mixed with other herbicides.

Given that reports of damage showing similar symptoms have come from Kansas, Iowa, Indiana, Michigan, and Ohio it seems unlikely that everyone is mis-applying the product.  I suspect one of a couple things may be going on.  Dupont may have underestimated the lateral extent of tree roots, especially for conifers that often have shallow, extensive root systems.  It’s also possible that Norway spruce and white pine are more sensitive to this product than whatever Dupont tested it on.

In the meantime stay tuned.  In case people haven’t figured it out for themselves, Dupont now recommends that applicators not use Imprelis near spruces or pines (see letter linked above). Landscapers or lawn service operators that have applied Imprelis should keep in touch with their state Department of Agriculture and their professional turf and landscape association.  Might be good to fasten your seatbelts, this could be a bumpy ride…

Excerpt from Davis et al. letter to Nature on natives vs aliens

In yesterday’s post I linked to a letter in Nature by Mark Davis and a number of other ecologists on the role and native and alien plants.  Unfortunately the journal requires a subscription.   Copyright laws prevent me from re-printing the entire article, however, below is an excerpt from the conclusion, which I think captures most of their message. 

"Most human and natural communities now consist both of long-term residents and of new arrivals, and ecosystems are emerging that never existed before. It is impractical to try to restore ecosystems to some ‘rightful’ historical state. For example, of the 30 planned plant eradication efforts undertaken in the Galapagos Islands since 1996, only 4 have been successful. We must embrace the fact of ‘novel ecosystems’ and incorporate many alien species into management plans, rather than try to achieve the often impossible goal of eradicating them or drastically reducing their abundance. Indeed, many of the species that people think of as native are actually alien. For instance, in the United States, the ring-necked pheasant, the state bird of South Dakota, is not native to the great plains of North America but was introduced from Asia as a game bird in the latter half of the nineteenth century.

"Specifically, policy and management decisions must take into account the positive effects of many invaders. During the 1990s, the US Department of Agriculture (USDA) declared several species of introduced honeysuckles to be alien (harmful), and banned their sale in more than 25 states. Ironically, from the 1960s to the 1980s, the USDA had introduced many of these same species in land reclamation projects, and to improve bird habitats. Recent data suggest that the agency’s initial instincts may have been appropriate. In Pennsylvania, more non-native honeysuckles mean more native bird species. Also the seed dispersal of native berry-producing plants is higher in places where non-native honeysuckles are most abundant (Gleditsch, J. M. & Carlo, T. J. Diversity Distrib. 17, 244-253 (2010).

"Clearly, natural-resource agencies and organizations should base their management plans on sound empirical evidence and not on unfounded claims of harm caused by non-natives. Another valuable step would be for scientists and professionals in conservation to convey to the public that many alien species are useful.

"We are not suggesting that conservationists abandon their efforts to mitigate serious problems caused by some introduced species, or that governments should stop trying to prevent potentially harmful species from entering their countries. But we urge conservationists and land managers to organize priorities around whether species are producing benefits or harm to biodiversity, human health, ecological services and economies. Nearly two centuries on from the introduction of the concept of nativeness, it is time for conservationists to focus much more on the functions of species, and much less on where they originated."

Ecologists weigh in on native-exotic debate

Charlie Rohwer, a frequent guest contributor to the Garden Professors, brought to my attention a recent letter in Nature by Mark Davis and 18 other ecologist entitled, "Don’t judge species on their origins." Davis is a leading authority on invasive species and author the book Invasion Biology. In their article, Davis and his co-authors make many of the same points that I’ve made here on the blog (Are natives the answer? Dec. 14, 2009; Restoration ecologists you need us – part 2. Aug. 9, 2010) regarding the native/exotic debate. The main point is that we need to develop a more pragmatic approach to managing landscape systems and this includes natives and exotic species; it’s not an either/or question anymore, not that it ever really was.

A couple of excerpts from their letter:

"It is time for scientists, land managers and policy-makers to ditch this preoccupation with the native–alien dichotomy and embrace more dynamic and pragmatic approaches to the conservation and management of species — approaches better suited to our fast-changing planet."

"Clearly, natural-resource agencies and organizations should base their management plans on sound empirical evidence and not on unfounded claims of harm caused by non-natives. Another valuable step would be for scientists and professionals in conservation to convey to the public that many alien species are useful."

The pragmatic approach that Davis and his co-authors (and I) advocate recognizes a several realities:

Exotics can fill many of the same ecological roles and niches as natives, Doug Talamy’s book notwithstanding.

Any inherent "ecological superiority" of natives over exotics has long since been negated by anthropogenic land-use change, alien pests, and climate change.

Attempts to eradicate alien species are largely warm-fuzzy exercises with little likelihood of success without liberal use of industrial-strength herbicides.

Gigantic hostas

I know Friday’s puzzle was a bit too easy – but I needed some way to discuss the giant hostas we have in our landscape this year:

We have had a very wet and cold spring.  While it was misery for us above-ground types, the plants absolutely loved the abundant water.  When the leaves open and expand on these continually-watered plants, they reach maximum size.  The hosta leaves in this photo aren’t the size of dinner plates – they’re more like turkey platters.

A word of caution to all of you with similar happy plants:  when the drier, hotter months of summer arrive, you’re going to have to keep these puppies well watered.  Otherwise, the leaves will soon turn crispy and brown around the edges.

One Of The Best Pictures I’ve Seen

Yesterday Jeff Hahn, an entomologist here at UMN (and author of the book Insects of the NorthWoods — a great field guide for Wisconsin and Minnesota), sent me a picture which reminded me of the dark ages and the methods that leaders of the past used to scare and intimidate their subjects as well as possible invaders.

This picture came to Jeff by way of Terry Straub, a Program Coordinator for Master Gardeners in Hennepin County.  Terry can’t remember where he got it from — The reason I’m mentioning this is that I’d love to give the person who originally took this picture credit for their brilliant (and somewhat disturbing) photo.