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.

Time for another WOW (Why oh why)!

During my nursery visits this summer I came across Taxodium distichum ‘Peve Minaret’, a dwarf cultivar of bald cypress.  I hate it:

Why? Because it’s a crummy specimen. If it’s not quite clear, here is a close up of the double leader:

I’ve ranted a couple of times about the production nursery practice of topping young trees to create fuller crowns (you can see those posts here and here). I’m constantly taken to task for this, with comments along these lines:

1) There’s nothing wrong with it. Customers like the look.

2) After topping the production nursery selects a new leader.

3) If the production nursery doesn’t select a new leader, then the retail nursery should.

4) If the retail nursery doesn’t, then it’s the customer’s job to do it.

5) If the customer doesn’t, then an arborist should catch it.

Somehow it’s always someone else’s responsibility to do the corrective pruning needed to prevent future problems. Yet I have not seen a cogent argument about why this practice is necessary (and “customers like the look” doesn’t count). In fact, a recent email told me I’m approaching this all wrong:

“I think it would be better for you to attack this problem by teaching the maintenance industry on how to remove a few poor branch angles, and make a profit on this, then to tell the consumer that they don’t know what looks good to them.”

Aha. So we get unsuspecting customer to buy a problem tree, then charge them again to fix it!

It’s not like I have to look very hard to find these trees in nurseries. Believe me, they’re everywhere, at least in this part of the country.

So…proponents of this practice. Convince me (1) that there is a valid, evidence-based reason for this practice, and (2) it’s okay for trees like this bald cypress to end up in retail nurseries.

Pruning perpetrators

Just when I thought I had you all fooled, Judy slipped in at the last minute with the correct answer – the “pruners” in question are deer:

The pruning ends when the deer can’t stretch any further, giving the tree its odd bell-shaped crown:

This is also a great demonstration of how pruning stimulates new growth – you can see the dense healthy growth at the base of the “bell,” even though this part of the crown normally would be much sparser.

Thanks for all the guesses!

Off with their heads!

About a year ago I posted my thoughts about the nursery production practice of heading young trees (“whips”) to stimulate lateral branching or columnar form or whatever.  (You can find this original column here.)  A healthy discussion ensued, much of which revolved around the need for appropriate follow-up pruning to ensure the development of a stable crown structure of headed trees.

Fast forward to last month, where a column I wrote for NPM (Nursery Production and Management) magazine hit the web.  And then the fan.

I made some people very unhappy with this article.  I had a lengthy and productive conversation with one such person last week, during which we agreed on many things, including (1) trees that are headed develop multiple leaders; (2) multiple leaders, however they’re created, need to be thinned to one central leader; and (3) uncontrolled multiple leaders can create hazardous conditions.  The bottom line, from a nursery production perspective, is that headed trees require regular pruning to create and maintain natural, structurally sound crowns.

And here’s my problem:  how many homeowners are going to perform this regular pruning?  Furthermore, how many homeowners KNOW how to perform corrective pruning?  We all know that number is going to be abysmally small.  Even for those situations where competent arborists could do this regular pruning, how many communities budget for this activity?

More troubling for me as a scientist is the lack of peer-reviewed scientific papers on this practice.  Though there are numerous papers documenting the effects of pruning, I can’t find any that specifically look at the long-term effect of heading trees during nursery production. You’ve heard all of us GP’s say it before – unless you can show us the data in a published and peer-reviewed format, we can’t regard anecdotes as anything but.

The nursery industry has invested a lot of time and money in a practice that leads to problems for which no one will claim responsibility.  Production nurseries wash their hands of the issue once the trees leave their facility.  Many retail nurseries don’t perform the necessary follow up pruning while the trees are in their care (do any retail nurseries do this?  Are they aware of the problem?).  Homeowners don’t receive information or training on how or why to perform corrective pruning.

What I’d really like to see the nursery production industry focus on is consumer education.  The metamorphosis of a sapling into a maturing tree is a wondrous thing.  Rather than interfere with the process, we need to cultivate patience as well as a respect for tree physiology.

Why bother having trees?

Sorry to be late with my post this week – I was away reviewing grant proposals.  It was interesting and useful work, but really drains your brain.  So with that being said, my post is long on pictures and short on words.

One of the things that bugs us GP types is poor plant placement.  Why bother planting a tree if you’re not going to allow it to grow naturally?  Here are some photos to mull over the weekend.  While I have lots of bad pruning pictures, these ones are chosen specifically because the trees were obviously poor choices for either site usage or size.

Because my sense of humor seems to have been left at the grant reviewing venue, I can’t think of amusing captions for these pictures.  But I’ll bet you can!  Just submit them in the comments sections, and I’ll repost the photos later next week with your contributions.

Photo #1

Photo #2

Photo #3

Photo #4

Photo #5

Shear lunacy

I subscribe to Digger magazine, the industry publication from Oregon Association of Nurserymen.  I am always curious about trends in the nursery industry and this magazine is a good way to find out what home gardeners are buying.

The cover feature of the May 2010 issue is on topiary. While I can appreciate topiaries in formal gardens – with dozens of gardeners to keep them shaped up – I think they are poor choices for most home landscapes.  Shearing plants to maintain a particular size or shape is a never-ending activity that most homeowners will tire of quickly.  Nevertheless, the magazine reports that topiaries are becoming more popular for home landscapes, especially along the East Coast. The article showcases the newer topiary shapes – stars, crosses, angels, even cacti – in addition to the traditional spirals and poms.

The article warns growers that skilled employees are needed to prune topiaries properly, and that the time commitment to create and maintain topiaries is significant.  One grower states “it’ll take a fair amount of time to shape it, and then you’ll be trimming it lightly a couple of times a year until you sell it.”

Curiously, the article says nothing about either the time commitment or pruning skills needed for homeowners who purchase topiaries.

Even more curious…the subsequent issue of Digger is devoted to sustainability. Seems a bit of a disconnect there.



Inspecting nursery plants, part IV

(Note:  this is a really LONG post.  Not in text – but in photos!  Sorry for all the scrolling.)

I don’t know about you, but after spending three weeks on my hands and knees looking for trunk rots, surface roots, and suckers, I’m ready to become bipedal again.  So today let’s look at trunks – and what shouldn’t be missing on them.

Many young trees have numerous short branches along their trunk, as shown in the photo below:


Unfortunately, many nurseries and gardeners think this looks scruffy, and respond by pruning these branches off, leaving a tree such as the one in this picture:

Personally, I think these trees look like lollipops, but aesthetics aside, this type of pruning can inadvertently damage young trees.  Their bark is often thin and sensitive to environmental stress – especially sunburn.  Without those short branches deflecting the sun from the bark surface, the living tissues under the bark can be killed, creating dead patches on the trunk:

How can you tell if the tree you’re considering has been improperly pruned?  Just look for those tell-tale pruning cuts, as a close examination of the lollipop tree reveal:

In time, these trees develop thicker bark, and the lower branches are gradually shaded out as the crown increases.  Be patient!  Let your trees be a little fuzzy when they’re young.  They’ll grow out of it.

To Prune Or Not To Prune, That Is The Question…

Dabney rules!

“Dabney! No! Wait!”  Just kidding. Dabney Blanton, our lovely and talented horticulturist, knows not to prune the Artemisia in the autumn.

I imagine most gardeners have experienced a frost or freeze by now [exceptions: our Southern Hemisphere readers (howdy to Jimbo)…or anyone in the deeeeep south].

The perennials here in Blacksburg have taken a couple of hits; time to start trimming things back. In the Hahn Horticulture Garden and in my own personal garden, we like to leave perennials and ornamental grasses up as long as possible – gives us something to look at besides mulch, plus the wee birdies enjoy it.

But some perennials just look yucky after a freeze.

Case in point: foliage of the popular perennial Artemisia ‘Powis Castle’ resembles graying Kleenexes, hanging on the tips of the branches.  HOWEVER, do not cut this back in the fall.  It, like many other shrubby perennials, is sensitive to early winter whacking, in my experience,  Buddleia and Caryopteris also fall into this category.  Apparently the severe pruning sends a message to the plant to break bud – new shoots can appear and then “zap!”  Wait until new buds appear in the spring, and be careful not to cut back too hard. I’ve killed a few that way, thinking I was doing them a favor.

“Cut ‘em back, cut ‘em back, waaaaay back!”

The best resource ever on maintaining perennials is Tracy DiSabato-Aust’s The Well-tended Perennial Garden. I should get kickbacks, as much as I’ve promoted this book! Truly a wealth of info – when should you cut it back, will it rebloom if deadheaded, don’t do [whatever] or you’ll kill it – all broken out by genus. Outstanding!

Dabney rules!

Carrot-top syndrome in white pine

I know a few folks out there are starting to believe that I’m just an apologist for the nursery industry.  While it’s true most of the nursery people with whom I work are hard-working folks trying to do their best to run a successful business and produce a quality crop, there are certainly some issues out there and I’ve got my share of pet peeves.  One of the things really that chafes my heiney is what I refer to as “Carrot-top” syndrome in eastern white pine (Pinus strobus).  White pine is one of the most commonly planted conifers in this part of the world.  White pine is native throughout much of the eastern US and is an extremely fast growing tree that makes a good ornamental when planted on the right place with room to grow.  It is also widely grown as a Christmas tree in the Upper Midwest as well and therein lies the rub.  Many nursery producers also grow Christmas trees and many Christmas tree growers also dig nursery stock.  The result?  White pines that have been heavily sheared as Christmas trees end up planted as landscape trees.  Once in the landscape, the upper portions of the trees will quickly resume rapid growth, with some shoots growing 2’ to 3’ or more per year; while the side shoots that had been repeatedly sheared barely grow at all.   After a couple of years the net result is neatly trimmed Christmas tree with a wooly beast growing out of its top.   What’s the solution?  Ideally producers should identify which portion of their trees will be sold as Christmas trees and which are destined for the landscape trade.  Christmas trees can be sheared to meet demands of that market while landscape trees can be pruned much more lightly to maintain a single leader and conical form but keep obvious layers of whorls.  The dilemma, of course, is that growers don’t always know which trees will end up and the Christmas tree lot and which will be dug for the nursery trade.  The other, more challenging problem is that, given a choice, 99 out of 100 garden consumers will choose the neat-looking Christmas tree for the landscape, unaware of the wooly mess that’s about to be unleashed in their yard.  The solution?  Education on both sides; making growers aware of the issue and making consumers realize that the only way to have a natural-looking white pine in your yard is to start with a natural-looking white pine.

Heavily sheared pines will retain the outline from from shearing for years while the top rages out of control.