Trunk teaser untwisted

Good guesses over the weekend on what caused the twisty looking trunk structure in Friday’s puzzle.  Here’s a larger photo:

Nancy and Paul both got this one – it’s two trunks fused together.  I have no idea whether the production nursery grew two saplings together on purpose or accidentally, but here’s one reason that this tree might be a problem down the road:

This area is ripe for disease, as water will collect in the crotch.  In fact, the area is already discolored and could be diseased already.

One thing I hadn’t noticed when I took the top picture were the price tags on the nearby pots.  They say it all – W(hy) O(h) W(hy).

Needless to say, I hope, is that you wouldn’t want to buy this plant.


A few months ago I was interviewed for an article where they asked me whether I thought that a deer repellant which was taken up into a tree would be a good idea. I said sure, great idea.  It would last a long time — something that most repellants currently don’t.  Well, I just saw the article and I must say that I’m not so sure that it’s a great idea any more.

It seems that the repellant that they’re talking about is basically a combination of hot peppers and DMSO.  The hot peppers have been around for a long time.  The DMSO not so long — just a few decades really (though there is very small quantity of naturally occurring DMSO in fruits) but DMSO has some properties that concern me.  When I was younger I was a competitive runner and I recall certain other runners using DMSO as a treatment for aches and pains.  I also remember a run-down house along one of my regular runs selling the stuff via a cardboard sign on the porch.  Looked kinda shady.  I haven’t seen much DMSO around recently, maybe because it isn’t legal everywhere — at least as far as I can tell.

DMSO is a solvent which crosses membranes, such as skin, very easily.  Apparently, if you use it anywhere on your body, it will make your breath garlicy.  In terms of toxicity — it isn’t considered very toxic. However, it has the ability to dissolve things, such as poisons (the insecticide imidacloprid for example), and anything which it dissolves can then cross the skin barrier very rapidly right along with the DMSO.

So to me this is a little worrying.  I don’t have much experience with DMSO, and I don’t have a problem with professional pesticide applicators who have the proper equipment applying DMSO, but I can’t help but wonder whether this stuff might be just a little too tempermental for the average homeowner to use.  Apparently the EPA has it now.  Here’s hoping that they’ll make the right decision, whatever that is.

Potted plants…really potted

A week or so ago my new friend Doug wondered about some gardening advice on the radio: would adding vodka to paperwhite narcissus make the flowers less “floppy?” The explanation he’d heard was that alcohol would burn the roots and reduce stem growth. Then today I received an email newsletter with the same intriguing information. This newsletter referred to a 2006 article that appeared in HortTechnology as the source of this information.

The study by Miller and Finan has generated a lot of interest in the gardening community, especially this time of year as people get ready to force bulbs for indoor blooms. Unfortunately, that enthusiasm isn’t evident among researchers. Neither the original authors nor any other researchers have continued this work; the HortTechnology paper has never been cited in any subsequent publication.

This is unfortunate – because inquiring minds want to know WHY alcohol causes narcissus stems to be shorter. Miller and Finan hypothesize that it’s simply an osmotic effect and allude to preliminary data that support this, “but additional work will be needed for confirmation.”

So I’ve looked into other scientific articles about ethanol and roots for insights into this phenomenon. There’s nothing on narcissus, but others have studied trees, forsythia, tomato and barley reactions to root-zone ethanol. In all of these cases, exposure to ethanol resulted in reduced root growth, decreased water uptake, and reduced leaf transpiration.

How does this translate to shorter stems and leaves? A reduction in water uptake and movement through the plant – that is, from roots through the stems and out of the leaves – can reduce movement of growth regulators like cytokinins from roots to stems and leaves. It can also mean that the plant contains less water and is less turgid as a result. Both growth regulators and cell turgidity are important in cell division and elongation. Reduced cell expansion will cause stems and leaves to be shorter and/or smaller as a result. This same phenomenon can be seen in plants grown under saline or droughty conditions: these plants are always smaller than their normal counterparts.

So what your grandmother used to warn you about is true – alcohol WILL stunt your growth!

So what to plant under power lines?

I’m going to add a bit more to Bert’s discussion.  Through the efforts of Dr. Eric Wiseman of Urban Forestry at Virginia Tech, we have a
Utility Line Arboretum (ULA).  Modeled after Dr. Bonnie Appleton’s original ULA for Virginia at the Hampton Roads research station, Eric’s includes many woody taxa suitable for planting in the vicinity of power lines (see a nice list of Bonnie’s favorite power-line-friendly taxa here).

Eric came to me with his plan in 2006 and we found some space in our Hahn Horticulture Garden to get it going. Funding came through from both the Virginia Department of Forestry and the USDA. He’s now up to 50+ specimens, including a “no-no” tree for a demonstration of relative size. The Urban Forestry Club students maintain the site and Eric uses the ULA for both education and outreach.  Our hort garden visitors are free to wander through the well-labeled display. Interesting story:  obviously, this would be more effective with a faux power line for scale, like Bonnie has at Hampton Roads. Our campus architect said “heck no.” Apparently Virginia Tech has gone to great lengths and expense to get all power lines/utilities below ground.  And the ULA is adjacent to the much-visited baseball field.

That’s Eric on the right, demonstrating proper planting techniques.

Our Horticulture department has a great relationship with Forestry; especially the Urban Forestry section. Their students take our Landscape Establishment and Urban Horticulture courses and we encourage our landscape contracting students to take Arboriculture. Several are minoring in Urban Forestry (or vice-versa). Just thought I’d share a nice success story – one that should make Bert’s maligned arborists happy!

Utility arborists: Give ‘em a break

One of our semi-recurring themes on the Garden Professor’s is our WOW’s or “Why Oh Why’s”.  As in “Why oh why do nurseries continue to sell invasive plants?”  Today, I’d like to turn things around a bit and look at a group of people that are often maligned by the public but, in fact, are getting a bad rap and could use a break; utility arborists.


Right tree, right place?

Utility arborists face a nearly impossible and unenviable task.   The goal of every electrical utility is to provide safe, uninterrupted power to their customers.  What do their customers do in return?  Plant large, fast growing trees under powerlines.  This invariably necessitates line-clearance pruning and, in some cases, tree removal.  So who takes the wrath of the neighborhood?  The oblivious homeowner who planted a row of Norway spruces under the lines? Or the trained professional arborist that does the trimming?


Betcha can’t top this…

Among the arborists with whom I interact, utility arborists are often the best trained and the most professional.  They have to be.  An amateur pruning around electrical lines suspended 50’ in the air in a bucket lift is virtually guaranteed a Darwin Award nomination.  Arborists can’t even win when they try to do the right thing.  Many utility forestry programs utilize directional pruning as an alternative to topping or removing trees.  When done properly, directional pruning allow trees to coexist with powerlines and enables neighborhoods to continue to benefit from large trees.  A survey by Mike Kuhns at Utah State a few years ago, however, found that homeowners actually preferred the look of a topped tree to a tree that had been directionally pruned.  Granted, directional pruning isn’t always pretty but it’s vastly preferable to topping or removal.


The utility arborists I know are dedicated and ‘tree people’ in the best sense.  If they lived in a perfect world, the right tree would always be planted in the right place.  Since it’s not they have to rely on techniques like directional pruning to help ensure safe and uninterrupted power.  So give ‘em a break.

Pesticides and Wildlife

If you follow this blog then you know that I write a lot about pesticides.  They’re something that I enjoy reading about and studying.  For whatever reason, I find them fascinating.  That said, they can be some of the worst things for wildlife.  But there are pesticides that are more “wildlife compatible” than others, so today I’m going to cover some of the worst pesticides that you can use in terms of wildlife, and some of the pesticides that might be more acceptable (though far from perfect).

First, here’s a brief rundown of pesticides that have been some of the worst wildlife offenders over the years.  Fortunately most of these are gone.

1.  DDT – long gone (though I know people who still have old bottles locked up in chemical cabinets here and there).  Modern evidence points to it not being as bad for human health (cancer) as many made it out to be, but it was a mess in terms of environmental effects — it built up in the environment (it is stored in the body and is not rapidly excreted — in large part because it isn’t water soluble — so when a predatory bird ate a small mammal who had DDT on (or in) it, all of that DDT would stay in the bird — and the DDT from the next mammal it ate, and so on — this is called biomagnification) and resulted in predatory birds producing thin-shelled, barely viable eggs.  Another problem with DDT was that it lingered for a long time — it doesn’t break down quickly.  It had other problems too – but the biomagnification and persistence issues were the most obvious and, at least to me, the scariest.

2.  Endrin – Relatively closely related to DDT, but a lot more toxic to a lot more animals and so a lot scarier.  Once upon a time this stuff was used to all but sterilize fields.  Toxic to everything that moves, and, like DDT, it built up in the environment.  This stuff was (fortunately) never really used by homeowners.

3.  Temik (aldicarb) – Nasty, nasty, nasty.  EXTREMELY high acute toxicity, AND it’s water soluble.  A pesticide which I have had to use in the past.  Apply it to a tree (I was working with pecans when I used it) and that tree’s foliage would be free of any insects.  And, amazingly, the stuff didn’t translocate to fruits and veggies – if it weren’t so darn toxic to things besides insects it would have been a great insecticide – some people still consider it a great insecticide.  This stuff was known for its misuse.  Apply it near a weed which deer eat and that weed would absorb the pesticide and poof! No more deer.  Agonizing death too.  Wolves and coyotes could be poisoned with just a little bit of tainted deer meat.  This stuff wasn’t supposed to be used by homeowners, but, again, it is known as much for its misuse as its use.

Fortunately most of those over-the-top killers are gone or on their way out.  Still, in your garden you do have the opportunity to use some poisons which it would be best for you to avoid if you’re interested in saving/protecting wildlife.  These poisons are called “broad-spectrum” poisons and they are preferred by many because they kill so many different types of pests.  Unfortunately being able to kill many kinds of pests usually also means that they’re able to kill many types of good creatures.  Many pesticticides such as sevin (carbaryl), pyrethrin, orthene (acephate), and sulfur are broad spectrum poisons that you should avoid, but here are some that, if you want to conserve wildlife, you should be especially wary of.

1.  Permethrin – This is probably the most used broad spectrum insecticide used around gardens today.  It will kill just about any insect which it touches and it lasts for about 10 days.  It is certainly effective, but it shouldn’t be used by anyone who wants to encourage insects or the birds who eat insects in their gardens.

2. Metaldehyde – This is a very effective slug poison.  It is both attractive and deadly to dogs and cats, and is thought to affect birds and small mammals as well though there aren’t as many documented cases of wildlife poisoning as there are of domesticated pets being poisoned.

3.  Copper sulfate (Bordeaux mix) – This is an organic fungicide that is often overapplied because it is considered safe.  It can limit the plants which grow in an area, and it is extremely toxic to aquatics – keep it away from water.  Finally – copper doesn’t break down – as you use it over the years it will build up in your soil – so try to stay away from it.

And finally, here are some which, if they are used properly, are less likely to affect wildlife.

1. Kaolin clay – it’s not popular, but it’s out there if you look for it.  This is a type of clay which it sprayed onto plants to protect them from insects.  It tends to work pretty well (it’s not perfect), but it has minimal effect on wildlife.

2.  Insecticidal soap – It will kill some insects that you don’t want to kill, but it’s a heck of a lot better than permethrin.  It is unlikely to hurt mammals or birds.

3.  Roundup – The controversial part of me wrote this.  Roundup has been implicated as doing all kinds of things to aquatic organisms, but, if it is only sprayed on the leaves of the plant you want to kill, it is not going to cause any significant environmental damage (besides removing a plant that wildlife may want for food).