The Garden Professors™

This gives “cutting the grass” a new meaning.

No, no, no.
NO.

Miscanthus sinensis, shaved into submission. — *Miscanthus sinensis* along the sidewalk in downtown Blacksburg, Virginia. Sheared into submission.

Textbook “right plant, wrong place.” Miscanthus sinensis is tough, drought tolerant, creates a nice screen, and if the late-blooming cultivars such as ‘Gracillimus’ and ‘Morning Light’ are selected, has little chance of seeding all over. After a few years in place, most cultivars are as wide (or wider) than they are tall. The lovely mounding/flowing habit is why this is the number one ornamental grass sold.

Mounded, rounded habit of Miscanthus as used at the Sarah P. Duke Garden (Durham N.C.). — Mounded, rounded habit of *Miscanthus* as used at the Sarah P. Duke Garden (Durham N.C.).

A better option – a very upright grass such as Calamagrostis x acutiflora ‘Karl Foerster.’ Regardless, this stuff needs to come out. Depending how long it’s been in the ground, a backhoe with probably be required. Or, they can continue carving it into a pillar.

The ins and outs of trunk injection

I am serving on a Ph.D. committee for a student working in Entomology and Plant Pathology who is defending his dissertation tomorrow morning. I’m taking a break from trying to plow through the longest dissertation in history: A 465 page tome on the use of trunk injection in tree fruit crops. A lot to wade through but a fascinating topic. Trunk injection, of course, is not a new topic. Some of the earliest references to injecting compounds into trees date back to Leonardo daVinci, who also suggested the ‘pipe model’ theory of tree architecture; the notion that total cross-sectional area of a tree is constant as you move up to higher and higher levels of branching.

daVinci's notes on branch architecture — daVinci’s notes on branch architecture

Trunk injection can be useful in lots of applications. We have done some research in my lab on the use of trunk-injected imidacloprid for treating ash trees for emerald ash borer. The compound is highly effective against the beetle but using C-14 radio-labeled imidacloprid we were able to demonstrate the flow up the trunk of ash trees can be ‘sectored’, potentially resulting in ‘hot’ and ‘cold’ spots in the crown where the adult beetles feed on leaves.

Injecting 14C-labeled imidacloprid into ash trees.

On the MSU campus our arborists have been successfully using trunk-injected fungicide applications to protect our remaining elm trees from Dutch elm disease (DED). Prior to the arrival of DED the MSU campus had about 3,000 elm trees; today we have less than 300. Under the current program the trees are treated with propiconazole in a three-year rotation; 100 trees each year. We still lose a tree or two each year but the program is largely effective.

Elm trees used to be a dominant feature of the MSU campus, now they are specimens.

One application of trunk injection of which I am dubious is for treatment of nutrient deficiencies. It’s not that trunk injection is not effective for this purpose; in fact, it is often highly effective. The problem is treating nutrient deficiencies with trunk injection just treats the symptom rather than the underlying cause. Here in the Midwest a common scenario is iron chlorosis in pin oaks. The fundamental problem is that alkaline soil conditions limit iron uptake. The solution? First, right tree – right place. Don’t plant pin oak if you have alkaline soils. Second, if it’s an existing tree, work on lowering the pH with sulfur or ammonium sulfate. Remember, trees have evolved or God designed them – take your pick – to take up nutrients through their roots. Dealing with that end of the equation is the best solution in the long run.

Trunk injection can be used to treat iron chorosis but can sometimes cause more problems. Injection of ferric ammonium sulfate burned leaves on this tree.

Conventional vs. organic agriculture – the battle continues

An article was published earlier this week comparing the nutritional content of milk from organically raised cows to that from conventional dairies. The principle finding in this report is that “organic milk contained 25% less ω-6 fatty acids and 62% more ω-3 fatty acids than conventional milk, yielding a 2.5-fold higher ω-6/ω-3 ratio in conventional compared to organic milk (5.77 vs. 2.28).” (ω-3 fatty acids are considered to be “healthy” and you’ve probably heard of them in association with fish consumption.)

Of course, the popular press has had a field day with this, with such headlines as “Study finds organic milk is more nutritious.” This of course is nonsense, because the researchers didn’t study the health effects on people consuming the milk. But for argument’s sake, let’s assume this might be true and move on to the study itself.

What researchers actually found was that cows who feed primarily on pasture grasses and other forages (the “organic” cows) had elevated ω-3 fatty acids compared to those receiving a primarily grain-based diet (the “conventional” cows). This isn’t new information – other studies (such as this one) have consistently demonstrated this.

The problem with this newest paper is the inaccurate terminology used to describe the study. It really has nothing to do with whether the cows are raised organically or conventionally – it has to do with what they eat. A better experimental design would have included multiple comparisons among “organic” cows (who by default are grass-fed), “conventional” cows that are fed a grain diet (typical with large operations), and “conventional” cows that are pasture-raised (common with smaller farms that don’t want to jump through the organic certification hoops). I’m betting that the milk from this last group of cows wouldn’t be much different from the “organic” cows.

The upshot of using such imprecise terminology is that the message is lost amid the furor of the ongoing organic vs. conventional agriculture battle. Readers erroneously jump to a value-based conclusion – i.e., organic is “better” than conventional.

In my opinion, there’s no excuse for this. The experts who reviewed this article should have pointed out the loaded language and insisted on a change in terminology. (You might be interested to follow the comments on this article, one of which alludes to misleading terminology.)

Does anyone really know how to handle weather ? – revisited

There are few things that bind us together like weather. No matter what a person’s socio-economic status, they get wet, hot, or cold just like the rest of us. Ok, if you’re rich enough you can afford to move where the weather suits your clothes, but if you’re like most of us, you have to deal with whatever Mother Nature sends your way. And, if you’re a typical American, few things give you more self-righteous satisfaction than knowing that out of the 300 million people in the country, YOU are the only one that knows how to cope with weather. So as this weekend’s winter storm brought wintry conditions to parts of the country that don’t often see snow, I could hear people chortling smugly from Buffalo to Fargo. Of course people in Dallas don’t know how to drive in snow; why the F#@$ would they? The chortlers also conveniently forget that that first full-on snow usually brings plenty of misery to northern climes as well.

It’s all basically a cycle. Someone, somewhere, sometime will be laughing at you and your neighbors. People from the Northwest snicker when schools in the Midwest delay their start because of fog, people in Michigan laugh when the South gets snow, and people in the South can’t understand the hysteria of a Midwestern heat wave. But thanks to Jimmy Kimmel, at least we can all laugh at southern California.

A Little Woodland Wonder

What’s that bit of green poking through the fallen leaves and forest duff? You’ll have to crouch down to get a good look at Wintergreen (Gaultheria procumbens). A mere 3-5″ tall, this teensy shrublet from the Ericaceae family (blueberry, azalea) has little oval leathery leaves, often mottled with purple or brown. A few urn-shaped pink to white flowers appear in early summer are followed by bright red berries. The berries persist well into the winter and help to distinguish it from similar-looking seedlings of mountain laurel or deerberry. When in doubt (or to clear your sinuses), break a leaf in half and inhale deeply. Yes, this humble little plant is the source of methyl salicylate – wintergreen oil – one of the active (though now synthetic) ingredients in IcyHot, Ben Gay, and other lifesaving remedies. Though non-scented versions are now available, that distinctive aroma alerts those nearby that you are an ATHLETE. Or perhaps just getting older*. Another common name is “teaberry” – hence the name of Clark’s chewing gum, flavored by the same compound.

Wintergreen is native throughout the Appalachians from north to south (USDA Hardiness Zones 3-8). Despite the pungent scent, when the acorn supply is low, deer will turn to wintergreen as forage. Birds, squirrels, chipmunks and others snack on the little red wintergreen berries, also redolent with the oil, and presumably have the freshest breath in the animal kingdom. In the garden, wintergreen does best in the shade of deciduous trees in acidic soil rich with leaf mold. Add wintergreen to the long list of N. American natives that have become wildly popular overseas but are under-appreciated here — it’s one of the top-selling nursery plants in Europe. Mix it up with Hellebores and hardy cyclamen to add some wildlife-friendly winter interest in the woodland perennial garden.

I can't find my own darn photo at the moment, but here's Gaultheria procumbens courtesy of Hedwig Storch and Wikipedia Commons. — I can’t find my own darn photo at the moment, but here’s Gaultheria procumbens courtesy of Hedwig Storch and Wikipedia Commons.

*Speaking of older, honk if you remember the “Teaberry Shuffle.”

Silence of the lamb chops

One of my ‘other duties as assigned’ this time of year involves serving as The Christmas tree Guy and responding to various media inquiries about Christmas trees. Last week I posted a link to a media story about Christmas trees on the Garden Professor Facebook page. That post drew a response from Kyle Fletcher Baker who derided cut Christmas trees as “murder of the innocent.” My initial reaction was, “Jeez, Kyle we’re talking about fir trees here not lamb chops or veal.” But Kyle’s post serves as a reminder that there are many people that object to cutting trees for Christmas decoration – no word on how these folks feel about cut flower arrangements but that’s another story. In some cases this objection stems from the belief that Christmas trees are cut from native stands of trees. In fact, virtually all Christmas trees sold at tree lots are grown on tree farms for that expressed purpose.

There is also a sizable portion of the population that believe artificial trees are more environmentally responsible than using a live tree. My personal opinion is this is a fairly small factor in most people’s tree buying decisions but the question persists and seems to get a lot of media play. The American Christmas Tree Association (a trade group that represents artificial tree retailers NOT tree growers) commissioned a life cycle analysis (LCA), which estimated cradle-to-grave carbon footprints for real and fake trees. The bottom-line of the study is that the impact of both is negligible. The tipping point is how far you drive to get a real tree each year and how long you keep your artificial tree. If you get your real tree close to home or combine getting your real tree with other trips, the carbon footprint of the real tree comes out better.

But if the thought of cutting a real tree is still more than your conscience can bear, there is a third option: a living Christmas tree. Many nurseries and Christmas tree farms offer container-grown or balled-and-burlapped trees that can be planted outdoors after the holidays. There are even companies springing up on the west that specialize in live Christmas tree rentals. These companies bring a tree into your house and then pick it back up after the holiday. Some will offer a certificate that the tree will be planted in a park or national forest after its display.

Working out the bugs

It’s December and I hereby vow to post every week from now on! I’ve actually been on the blog behind the scenes for the last several weeks troubleshooting the archives. We transferred over four years of material from the old site, and there are still some rough patches. And that’s where you can help.

If you have been browsing the archives (listed on the right hand menu) or searching for topics (the search box is in the upper right corner just below the Garden Professors banner where the little magnifying glass lurks), you may have found odd line breaks, broken links, missing pictures, etc. in the posts and the comments. Or you might be searching for a particular post on the internet and end up with a 404 error page instead of the blog. It’s easy for me to fix these problems, but finding them takes some time.

So if you, our faithful readers, find these problems and post them below. We’ll have a contest: the top three contributors of bugs, breaks and boo-boos will each win a swell prize! (Not telling what the prizes are. You will have to wait and see.)

In the meantime, enjoy this photo of my husband Jim as we searched for the perfect Christmas tree last Friday.

It was a dark and stormy night

A wild and wooly night for many of us last night. A powerful line of storms moved through the Midwest yesterday afternoon and evening, spawning numerous tornadoes, primarily in Illinois and Indiana. Here in Michigan we were spared the tornadoes but had to cope with a long night of high winds, gusting up to 70 mph along the Lake Michigan lakeshore.

The high winds and heavy rains lead to widespread tree damage and power outages. Dealing with a yard full of damaged trees can be an overwhelming and sickening feeling for homeowners. If you are a homeowner or someone who advises homeowners, there are several good resources on the web to assist with the process of assessing storm damage to trees after a storm.

The National Arbor Day Foundation has a storm recovery website that provides practical tips for dealing with storm damaged trees. The website also includes resources for media including press releases and images that are useful for educating the public on steps to take during storm recovery.

The Minnesota Department of Natural Resources also has useful storm recovery information on their website.

For those dealing with storm damaged trees keep these points in mind:

-Stay at least 25 feet away from any downed power lines and contact local authorities to report downed lines.

-Damaged trees and hanging tree limbs are extremely dangerous. Trees that are damaged in storms often have decay or other hidden defect and can drop without warning. Walk around – not under – damaged trees and limbs. Keep children away from damaged trees.

-If you are unsure if you can safely remove a limb or damaged tree, always err on the side of caution and contact a professional arborist or tree service company.

-Be wary of ‘door-knockers’, individuals that descend on storm-ravaged areas that offer to perform tree clean-up or removal. Reputable, professional tree service companies rarely, if ever, solicit business door to door. Working around damaged trees is dangerous work that requires professional training and equipment. Look for arborists that are insured and certified by the International Society of Arboriculture.

Hello Charlotte!

I’m sure you haven’t been wondering where I’ve been for the past five months or so, but just in case you have, I’ve been reshuffling my life and relocating. Where am I now? The family and I have moved to Charlotte, North Carolina where I now work at Central Piedmont Community College. Why? Because we wanted to be closer to family, we wanted a warmer climate, and I wanted to spend more time teaching. That said, I had a great time at the University of Minnesota and have only good things to say about my time there.

The great thing about my new job is that I have the opportunity to teach a diverse student population a broad spectrum of classes. This coming semester I’ll be teaching five classes including Specialty Crops (we’ll be concentrating on hydroponic systems for growing veggies – it’s a great way to learn about what plants need to grow), Plant Propagation (My favorite! Everything from cuttings and seeds to budding and grafting), Greenhouse Management, Applied Plant Science and Plant Materials I. And Hey, if you live near Charlotte, I’d love to see you in one of my classes! CPCC is one of the most affordable schools in the country and the classes are open access – in other words anyone can sign up! Since I don’t have the chance to do as much research as I did in Minnesota, I’ve compensated by having my students conduct experiments in the classes – and we’ve had a lot of fun. We’ve done everything from extracting essential oils using cold fat and steam extractions to rooting cuttings using 2,4 D and spiking the atmosphere with carbon dioxide using soda bottles. I’ll be posting about all of these projects in the coming weeks. Meanwhile, it looks like vinegar based BBQ with fried okra for dinner!

My favorite on-line conifer resources

Posted by Bert Cregg

I just wrapped up putting together a species profile on grand fir (Abies grandis) for Great Lakes Christmas Tree Journal, which is the professional trade publication of the Michigan Christmas Tree Association. I do a lot of articles and presentations on conifers and while I draw on my personal experience and background as much as possible, invariably I’ll need to consult some references. Here are some resources that may come in handy if you need to develop a presentation or article or just want to know more about conifers.

Silvics of North America
Silvics is a forestry term that refers to the “study of the life history and characteristics of forest trees especially as they occur in stands and with particular reference to environmental influences.” Back in the day, just about every forester worth their salt had a weathered and dog-eared copy of Silvics of North America on the bookshelf. Today it is available on-line. Silvics contains lots of basic information about trees species; where they grow, how fast they grow, common best problems, and their genetics. Silvics also includes range maps from Dr. Elbert Little, which are a handy reference when you need to know whether or not a species in native in particular location.

Gymnosperm database
Chris Earle’s website is a botanical tour de force. It covers all gymnosperms, not just conifers but, of course, conifers make up the biggest portion of the site. The Gymnosperm database includes species descriptions for essentially every conifer in the world. Many species descriptions also include images. Earle discusses taxonomy of conifers, which for many species, is taking more plot twists these days than an episode of ‘Law and Order’. There are often interesting tidbits under enthnobotany for many species. Bottom line, you can look up just about any conifer species you know on the database and learn something you didn’t know.

American Conifer Society Database
The previous two resources deal primarily with conifers in their native environment. The ACS is dedicated to the Horticultural aspects of conifers. The ACS database includes hundreds of species and thousands of cultivars. For Picea abies alone the database includes over 200 cultivars. For each cultivar the site presents information on hardiness zone, growth rate, form, color and other characteristics. Many descriptions also include photos.