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My wife and I were in Washington DC a few weeks back for a wedding.  I’ve been to DC a handful of times and it is one of my all-time favorite places to visit.  I love history so the memorials, monuments and Smithsonian museums are all high on my list.  But DC has a lot to offer plant geeks as well.  In honor of Memorial Day and the unofficial start of summer vacation season, here are my top three DC Horticultural Highlights.

National Botanic Garden.  Located nearly adjacent to the US Capitol, the Botanic Garden is easy to miss if you’re not looking for it.  The garden is comparatively small but offers a nice respite from the hustle and bustle (and interminable school groups) of the rest of the National Mall.  It’s also a cooler oasis to beat the heat if you visit the Mall in the summer and offers some unique views of the Capitol.  The conservatory has great on-going and rotating exhibits.  A current one was on medicinal plants.

The National Arboretum.  The Arboretum is a little more of challenge to get to and probably best if you have a car.  Some highlights include the Gotelli collection of dwarf conifers, the grove of state trees, and The National Bonsai & Penjing Museum.  Be sure to check on hours of operation before you go.  The first time I visited the Arboretum I arrived at 4:30 thinking I would have a several hours of prime late afternoon and evening light for pictures, only to find out they closed at 5:00.

Arlington Cemetery. Arlington is a special place is so many ways.  If you’re an American, these are images steeped in our collective consciences; the tomb of the Unknowns, the Kennedy gravesites, the Challenger memorial, and tens of thousands of headstones marking those that gave the last full measure of devotion.  The grounds are wonderfully tended and, like the Botanic Garden, provide a break from the din on the nearby National Mall.  The Cemetery grounds include dozens of memorial trees and several state Champion trees. Motorized trams are available but if you can walk a couple miles it’s a fascinating and moving place for a stroll.  Arlington is easily accessible by DC Metro or walk across the Memorial Bridge at the Lincoln Memorial end of the Mall.

Today I’m going to throw up a post that’s a little link-heavy, but I encourage you to follow these links because they show how prevalent the technology is that I discuss.  And a trip to the garden center will quickly show how infrequently this technology is used.

It’s frustrating.

Why the heck do we still buy plants grown in containers using 1950s technology?  I was reading Bert’s post this week about how to treat container grown trees before planting and also considering a somewhat similar experiment which I conducted about a year ago (stats are in and support my points in that article), and I couldn’t help asking, why do we put ourselves through it? 

The technology is out there for us to produce great root systems by using new types of pots that have become available over the last few years. Look up High Caliper Growing System, Rootmakers (which also includes RootTrappers — we’ve been using these for years), Smart Pots, Superoots, — and there are other systems out there too – all of these systems greatly reduce circling roots and are relatively easy to use.

Do we ask for record players or black and white TVs when we go to the electronics store?  No!  We want MP3 players and big flat screens.  So why are we content with plants grown in containers that come straight from 1954 in our garden centers? 

If we would just start to demand that garden centers and nurseries provide container grown plants with better root systems we’d get them – because they are out there.  But we need to be proactive or we’ll be stuck in the past forever.

It’s been a busy spring around the Cregg lab.  In many ways, it feels more like mid-summer than mid-May.  One of the items my students and I have been with is installation of the Social Media Designed Tree Transplant Study (SoMeDedTreeS).  As loyal Garden Professor blog readers will recall, we conducted a Survey Monkey poll last fall to help develop a study plan to investigate tree transplanting practices of container-grown trees.  Based on the results of the survey we designed a study to look the effects of root-ball manipulation and post-transplant fertilization on 96 planetrees.  

Well, the time has arrived.  Last week we completed the first of two installations of the study – the second will be installed at the MSU Beaumont nursery soon.  Graduate research assistant Dana Ellison and summer research intern Aniko Gaal finished planting the first 48 trees last week at the MSU Hort Farm.  These two did yeoman’s (yeowoman’s?) work in handling the trees, applying the treatments and getting in the trees in the ground.  

Sometimes the best man for the job is a woman…

All of the trees are ‘Bloodgood’ planetrees that we have grown on in 25 gal. containers for past two years. The study was installed as a 3 x 2 factorial in a complete block design.  We have 3 root-ball manipulations: “shaving” the outer 1 in. of the rootball to remove circling roots; “teasing” apart the outer part of the rootball to pull appear circling roots; and “control” just pop off the container and drop ‘em in the hole.  The second part of the design is fertilization; with or without.  This results in 6 combinations (3 root-ball manipulations x 2 fert levels) times 8 reps = 48 trees total. 

Graduate Research Assistant Dana Ellison teases apart a root-ball

Summer Intern Aniko Gaal shaves a root-ball. Step one: remove the ‘pancake’ of roots  from the bottom.

Not to complicate life too much but I am considering a change to the protocol.  We will continue with the original rootball manipulation and fertilization trial at the second installation at Beaumont nursery.  In each test we would have 48 trees and 8 reps, which is better than a lot of landscape tree studies.   But given our recent discussion about mulching, I propose substituting with a mulch vs. without mulch treatment instead of the fert vs no fert at the Hort Farm installation.  We will water the trees once or twice a week to help get them established and then cut off the irrigation after about a month (simulating a city forestry department getting a budget cut and having to lay-off its temporary crews).  We will monitor soil moisture and tree water status in the subsequent months.   

Trees after planting

Before I make the change in the study, however, I’d like to get some feedback from our readers lest anyone feel there’s been a bait and switch.

OK, here’s a question for you.  How much would you pay for an online course taught by professors (perhaps garden professors?) about plants and gardening including things like fertilizers, pest control, etc.?

Hour long lectures once a week (through Skype or something similar) with an additional 1/2 hour built in for questions?  12 weeks of lectures.  No college credit.

I haven’t talked to the other garden professors about it — this is purely a hypothetical question for now.  I’m just wondering if there is interest in this kind of thing, and if so, how much. 

Thanks for your responses!

I’ve had an on-going discussion – OK, argument – with a fellow faculty member who does research on social dimensions of forestry, including urban forestry.  She contends that we basically know everything we need to know about growing trees in cities and that the real underlying problems in urban and community forestry these days are social issues.  This, of course, means that funding for urban forestry research, what little there is, should be directed at social sciences.  Needless to say, as a tree physiologist, I can point to lots of examples of trees in cities in pitiful conditions and under stress.  To which, my colleague would hasten to ask, “Is it because the urban forester (if the city can afford one) doesn’t know any better or because they don’t have the resources to do anything about it?”  Which is a valid point.  Most of the urban and community foresters I know are dedicated, well-educated, highly professional, and woefully under-staffed.  The Greening of Detroit, a community-based urban forestry non-profit, got its start several years ago because the city could not afford a tree planting program.  The city forestry department dedicated its meager resources to tree trimming; going into triage mode on a 125-year back-log of tree maintenance.  Why would a city plant trees when it can’t even care for the ones it has?

What got me thinking about this was a New York Times article on a rash of tree grate thefts in the city. http://cityroom.blogs.nytimes.com/2012/05/10/if-its-made-of-metal-thieves-increasingly-have-an-eye-for-it/  With the rising price of metal such as iron and copper, thieves are making off with just about anything made of metal including tree grates and man-hole covers.  We can probably start a whole other debate about tree grates and tree pits and whether they are effective, but, in any event, the city forestry department will now have to devote resources to replacing the stolen tree grates and figuring out ways to keep the replacements from disappearing as well.  

I’m not ready to concede that we know everything we need to know about growing trees, but the longer I’m at it, the more I see the need to integrate the biological and the social elements.  We can develop the best tree establishment and tree care protocols in the world but if there no money or no public support to implement them, it’s all for naught.

I’m not going to sugar coat it – I’ve been too cavalier in recommending iron phosphate for slugs and snails. 

A few days ago Erin Harris put a comment in my post about dandelions asking whether those iron phosphate baits you can buy for slugs might also be toxic to earthworms.  The answer is yes – they might.  And not only that, these iron phosphate baits can also be toxic to other animals such as dogs.

How bad might these products be for dogs and earthworms you ask?  I don’t think anyone knows exactly, but to my knowledge this is the most recent paper on the subject.  And here’s an abstract on dog poisonings.

Now, based on the data I’ve seen on poisoning incidents, iron phosphate is less likely to poison your dog than its closest competitor, metaldehyde (though the iron phosphate seems more likely to hurt earthworms than the metaldehyde).  I’m not going to stop recommending iron phosphate – Still, I can’t recommend it quite as freely as I have been in my talks — I need to add some real caveats. 

So then the question is, how did I not know about the potential problems of iron phosphate?  Simple.  I assumed that the compounds listed on the active ingredient list were really the only ingredients I needed to think about.  Silly me.  Just like Round-up, and almost any other pesticide you can name, there are other ingredients that help the active ingredients work — and that could cause issues.  For Round-up, the soaps mixed in there to help the product stick can hurt frogs or other amphibians.  For Iron phosphate, the extra ingredient that could do some damage is EDTA.

So, you’re asking, what is EDTA?  EDTA is a chemical which makes metals more soluble, called a chelate.  In iron phosphate products EDTA helps the iron to be taken up into the body of the snail or slug making it work much better than it might otherwise.  EDTA is also used in fertilizers so that elements (usually iron) are taken up more readily (because they’re soluble).  But because EDTA makes metals more soluble, it also helps them get to places they shouldn’t go – like into an earthworms body.

Now don’t go thinking EDTA is bad.  It’s not.  In fact, if you ever ingest lead or some other metal you’ll be thankful for EDTA because it is used to help clear potentially toxic metals from the body.  EDTA is even present in some of our foods for various reasons.  That said, as with any chemical (including water!), it is possible for EDTA to do things we don’t want it to do in the wrong circumstances.   And that’s why we need to be more careful with its use.

As I said before, I’m still OK with iron phosphate products, especially as they compare to metaldehyde products, but you can bet I’ll be spending more time stressing its drawbacks.  I’ll also be spending more time touting beer.

For slugs of course!

Now, a question for you.  These iron phosphate products are currently listed by the OMRI (Organic Materials Review Institute) and some labels list it as being safe to use around pets and wildlife.  If the products include EDTA, should that be the case?  (You can look up EDTA in Wikipedia if you want to see how it’s made.)  Are you comfortable with using EDTA in organic production?  Does it matter to you if it’s used as a fertilizer vs. as an ingredient in a pesticide?

Well, students just finished finals here at MSU so I suppose it’s appropriate we put our faithful GP readers through their own gauntlet of quizzes…

Top marks to Terry for determining the damage on the conifer seedlings was due to incomplete overlap on the sprinklers the grower used for frost protection during our most recent freeze.  Our record-setting March warm up pushed budbreak ahead by about a month in most locations in the state.  Fruit crops (cherries, grapes, blueberries, and peaches) have been devastated but nursery crops and landscape trees came through relative unscathed until the freeze the weekend before last.

I know Linda normally handles quiz duties, but I received a couple of intriguing pictures last week.  Rather than just tell you all what’s going, I thought we’d have a little sport with it.

The photo below was taken last week ago at a container seedling nursery in western Michigan.  These are trays of container-grown spruces.  Most of the seedlings are green and growing but some are tip-damaged – with a specific pattern.  What’s going on and what caused the pattern?

Last August I posted some photos from a field tour in Austria where we saw an organic Christmas tree farm that used Shropshire sheep as their principle form of weed control.  The particular breed of sheep is suited to the task since they will graze on grass and weeds but not on conifers.  Since then I have shared the pictures elsewhere and found out the Shropshire sheep are also employed in the U.S. and the U.K. for similar purposes.  Recently, I have had several people share websites for a service known as ‘Rent-a-Ruminant’.  As with the Shropshire sheep, these services use grazers to control vegetation, but instead of sheep these companies use goats. 

Unlike sheep, goats are much less selective grazers; so call these guys in when you’re in need of land-clearing or invasive species removal.  I have seen Rent-a-Rumant advertised in the Pacific Northwest http://www.rentaruminant.com/goats-clear-land.html and in Australia http://thebegavalley.org.au/24484.html so clearly this is a widespread idea.   And, I suppose, an example of an old idea that’s new again.  As many GP blog readers probably know, I have issues with the ethics (not to mention efficacy) of exploiting grade-school children to pull garlic mustard or purple loosestrife in the name of invasive species control.  But using goats to control invasives?  That might be a solution everyone can get behind

Not baaaad work if you can get.  Rental ruminants chomping on English ivy in the Northwest. (Just for you, Linda)