Vertical Gardening at -7 F

I've been working on compiling a list of tough natives and climate adapted species that could survive in a vertical garden application through our Boise winter with little or no care. In May, I was commissioned to build my first "xeric" vertical garden, so I used this opportunity to try out both drought AND cold tolerant plant varieties. 

Although I'm very interested to see how true Idaho natives like Eriogonum (Buckwheat) would do in a vertical installation, I settled on cultivated plants that are pretty easy to find in Boise nurseries: Hemerocallis 'Double Moses Fire' , Nepeta 'Walker's Low' , Artemisia 'Powis Castle' , Yucca, Sedum and Stachys byzantina 'Helene Von Stein'. 

The first pic shows the wall right after it was installed at the end of May. The second shows growth after the first six weeks. 

In a classic case of be careful of what you wish for, I was hoping we'd have a real winter here in Boise this year so I could get a true sense of the durability of these plants.  My wish has been granted. I snapped some pics of the wall a few days ago after we'd dropped convincingly below zero more than once. Alive, but looking pretty freeze dried. The Artemisia, Stachys and Yucca are bravely continuing to provide evergrey winter interest, but everything else has pretty much given up. Some closeups... Tough-as-nails Lamb's Ear (Stachys byzantina) still hanging in there. Sedum tetractinum looking a lot like the frozen grapes my mother fed me as a kid. Artemisia 'Powis Castle' taking the frigid weather in stride. Yucca rostrata 'Sapphire Skies' looking exactly the same as the day I planted it. We'll see how things are looking in February and then again in May.  I'd love to get any xeric/cold hardy plant suggestions for vertical applications!

Tree Removal: A Day in the Life of a Tree Climber

At Willowglenn, the majority of the tree work we do consists of structural and maintenance pruning. When someone approaches us about tree removal, I generally try to talk them out of it.  I figure there are plenty of companies out there that will gladly take your cash to remove a tree for any reason.  By taking a conservative stand on tree removal, I hope to counterbalance their eagerness.

Tree removal is, however, a critical element of urban forest management.  Boise's moniker as the City of Trees is nice but belies the fact that our urban forest is a human construct and needs to be managed as such.

Diseased, damaged or dangerous trees obviously need to be removed but so do trees that have the potential to cause a Hatfield and McCoy style feud between neighbors.  This particular pine had been planted right up against the property line, and had a taken to leaning towards the neighbors house.

Even worse, the pine also provided ladder fuels right up to their wood shake roof.















A nice looking Red Oak was also about 10 feet away and really needs more space to develop an even canopy.  The pine had  also long since shed its lower juvenile limbs and didn't even provide the  screening that was originally intended.  It was definitely time to get rid of the tree.

View of Table Rock atop the pine

The challenge, of course, for most urban tree removal is how to do it in such a way as to not punch a hole in a roof, collapse a gazebo or flatten someone's new 30K ipe deck.  Fortunately, there was a narrow pea gravel footpath that ran directly under the tree.  So, rather than utilize a complicated rigging system, I decided to take the tree down in firewood size pieces and drop it on the path below (convenient, as it's eventually headed to our wood stove anyway).

When I bid a tree removal job, I factor in a few different things such as: what kind of tree (hardwood? softer wood?), height, high-value targets around the base of the tree, and how many leaders the tree has. Multi-leader trees take the longest because you're essentially removing multiple trees within the canopy.  This pine had five separate leaders so I knew that I was looking at a full day's worth of work for myself and a ground crew.

Aside from knowing that I'm going to smeared in sap, I usually look forward to working in pines.  An even lattice work of branches (most of the time) makes it pretty easy to move around.

The first thing I do is find the tallest leader in the tree and secure my cambium saver as high up as it will go.  This is where my climbing rope is attached to the tree.  Attaching myself to the rope requires tying on the end of one side of the rope with a termination knot and attaching midway on the other side of the rope with a friction hitch knot that allows me to self-belay.  My favorite hitch knot is called a Valdotain Tress.  With this hitch, it's easy to ascend the tree but catches you should you slip (by putting a kink in the rope).

      






I like to minimize the amount of chainsaw time as much as possible when I'm roped into a tree, so I begin by removing all the branches with a 4" caliper or smaller with a hand saw.

Once that's done, I begin using a chainsaw and a steel-core "flip line" as redundant fall protection just in case I accidentally cut through my climbing rope or my harness.














Slowly, I work my way down the shorter leaders and then move on to removing the main leader.

 

With the help of my hard working ground crew, we were able to complete the removal just as we started losing our light for the day.

Done!

Winter Tree Pruning

A few days ago a respected local gardening celebrity published an article cautioning her readers to skip winter pruning of trees because of potential freeze damage. There were many other good points made in the article but this piece of advice really stuck in my craw.

OK, full disclosure first: I'm an ISA certified arborist who also runs a full service landscape company. Why is this relevant? Mostly because of the seasonal aspect of how I make a living. My inspirational St. Crispin's Day speech for my crew this morning did little to change the fact that it was 18 degrees. When the ground takes on the characteristics of granite, tree pruning becomes our main source of work. 

So my initial reaction to the article was something along the lines of this person is trying to steal bread from my child!

Deep breath.

Most arborists I know like to prune in the winter because the tree structure (or lack thereof) can be clearly seen without a cloak of leaves, making it easier to determine pruning decisions. Personal opinions aside, it is incumbent for an arborist to prune according to ANSI A300 pruning standards (the arborist's bible).This is what the guide has to say:

The best time to prune live branches depends on the desired results. Removal of dying, diseased, broken, rubbing, or dead limbs can be accomplished any time with little negative effect on the tree.            Growth is maximized and defects are easier to see on deciduous trees if live-branch pruning is done in the winter before growth resumes in early spring. Pruning when trees are dormant can minimize the risk of pest problems associated with wounding and allows trees to take advantage of the full growing season to close and compartmentalize wounds. (Best Management Practices Tree Pruning Companion publication to the ANSI A300 Part 1: Tree, Shrub and other Woody Plant Maintenance-Standard Practices, Pruning, pg. 25 para. 1 &2)

             

For more info about winter pruning, check out these sites:

Trees Are Good
Chicago Botanic
Arbor Day
Minnesota DNR

Southern Magnolias in a Northern Town

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As our urban forest disrobes and a steely-gray nuclear winter sky descends over Boise, I'm reminded again of how much I appreciate the glossy, evergreen foliage of the Southern Magnolia (Magnolia grandilflora).

Here are some interesting tidbits about the Southern Magnolia in our climate:

• There is a wide degree of variability amongst the many available cultivars, with Edith Bogue, Victoria and Bracken's Brown Beauty consistently overwintering well in our SW Boise Zone 6 property (there are reports that Edith Bogue even grows in Chicago).
• Winter desiccation from dry, cold wind is really tough on these broadleaf evergreens. If you live in a very windy, exposed site or south of Lake Hazel, forgetaboutit.
• In our climate, Southern Magnolias drop their three year old leaves in the spring and early summer (much to the consternation of those unfamiliar with this cycle!).
• Our Southern Magnolias need no more water than an average hardwood tree and have happily grown without fertilizer of any kind in our nasty, caliche "soil".
• Fragrant blossoms begin to appear late spring and continue into mid-summer.

Here's a picture tour of Southern Magnolias around Boise:

Ruby red seeds of summer's spent flowers juxtaposed against  lush evergreen foliage.

Lake Heron planting in 2003.

Ten years later! Yes, a bit close to the foundation,  but in my defense we had just visited Georgetown where Magnolias planted within a few inches of brick walls are de rigueur

Another 2003 planting....

Same tree, today (again, in the Georgetown style).

Edith Bogue in our garden

The closely related Magnolia virginiana. Flowers have an intense citrus aroma.

A new, apparently hardy cultivar that my friend Steven Gossett grew from a seed he harvested from Spain. He calls it Granada.

Another cultivar in Steven's nursery, -24. Fortunately, we haven't had the recent opportunity to see if it lives up to the name!

The last two are significant because they both survived -20F -22F back in the early 90's December 22nd of 1991. So those of you who think we live in Zone 5, take note (you know who you are).

Foothills East

The largest Southern Magnolia I've found in Boise is near Winstead Park. The oak behind it adds some nice contrast. The owners have told me that after -20 F -22F, the tree completely defoliated but stubbornly pushed out new leaves in the spring.

Same tree, different angle

Kiva

The ruins of a 500 year old kiva was recently unearthed in the Boise foothills...

OK, well maybe not, but that's the feel we're going for on a new landscape construction project in the El Paseo Subdivision on the west side of Warm Springs Mesa.

Granted, the Pueblo culture didn't make it up anywhere near Idaho, but it's interesting to think how they would have used our local rock in their distinctive architectural style.



It wouldn't be the first time I've looked to the southwest for inspiration in our hardscape construction.

Four Corners region

Highlands in Boise

The Boise foothills is full of its own history though- this home is being built within a stone's throw of  Trail #14, which runs along the course of a tram that was once used at the Table Rock quarry. You can still see some of the dry stacked sandstone walls that were built over a 100 years ago.

Installing Andesitic Idaho Flagstone

Helleborus orientalis  First flowers in our garden!

     

I get as excited about spring flowers as the next enlightened, sensitive guy, but the thing that really tells me the season has started is when we get our first flagstone installation for the season.

This flagstone walkway I built for a  bungalow in the North End took me the better part of of last Monday to complete. There is truth in the term "hardscape".

The coolest thing about the walkway, other than the fact that our
client paid us instantly (thanks Beth!), is that all the stone comes from an easy drive's distance from Boise.

The downside of using this local stone is that while one side of the stone is generally pretty flat, the other side isn't. The stone also doesn't have a uniform thickness like Arizona sandstone, or some of the other rock quarried in Idaho. This makes installation of our local stone a little tricky.

Dreaming of flat bottomed pavers

Pavers and stones with even thickness are pretty straightforward to install. You have to...

- excavate the site
- install a course base and compact
- install a compacted & screed sand base

...and then you're ready to lay down your flagstone. If you've done a good job with your prep work, this last step can be completed pretty quickly.

Our local stone requires a couple more steps.

I use thicker pieces as a "keystone" within the patio to lock in thinner pieces of flagstone.
This requires you to excavate a bit of the sand you've worked so hard to compact.

I lock in the rocks by using a rock hammer to compact sand around and under the stones.

And then add another rock...

And then another 80 or so pieces until either I'm done or I can no longer hold on to my rock hammer.

I finish up each flagstone project by sweeping sand over the top of the rocks, filling in any voids to prevent stones from rocking.

Happy hammering.

Fruit Tree Pruning

People are indignant when I refuse to discuss fruit tree pruning in my basic tree care classes. Ornamental tree care couldn't be more different than pruning for fruit production so I rarely bring up the topic in the course of my presentations. These folks leave my classes disappointed and usually a little angry. Such is the life of a public speaker.

But I think any arborist should be at least a little uncomfortable uttering phrases like "reduction cuts" and (even worse) "heading cuts", so I'll start these instructions with the caveat: don't do this to shade trees. Really. Because I'll have to hunt you down if you do.

I keep my fruit tree pruning goals pretty simple:

1. Reduce the crown of the tree to short(ish) laterals that,
     a. are accessible from the ground or a short ladder and,
     b. reduce the possibility of branch failure under fruit load.

2. Keep the center of the tree open for good air circulation (and because it's hard to get fruit from the interior of the tree anyway).

3. Train the lateral branches to form an open lattice work to allow adequate light to the fruiting branches.

4. Remove dead, diseased and wounding crossing branches

Upright branches are vigorous in their growth, but laterals are better fruit producers.

Upright branches before pruning.

Half of an apple tree pruned to lateral branches.

Another shot of half the tree pruned.

First completed apple tree

Another completed apple tree at the same property

Another shot of the same tree.

Hey, did I happen to mention that if you do this to an ornamental tree I'll break your knee caps?

Next week I'm going to write about what happens when you do this to an ornamental (to the tree, not you) and the restorative pruning needed to, um, restore it.

Boise Right-of-Way Pruning

The City of Boise requires a special license in addition to ISA Arborist certification for any tree trimming in Boise Right-of-Ways. A few of our clients have recently asked for pruning in these areas so I met with Boise City Arborist Dennis Matlock today in order to be evaluated and licensed.

We met at a property a couple blocks north of Warm Springs with an approximately 40 year old maple that needed some basic maintenance pruning.


After roping in, my first target was the  removal of the many dead branches in the canopy.

The second priority was the removal of crossing subordinate limbs that were wounding major scaffold branches. 

Roped into a high branch in the canopy, I also found and removed several large broken off branches or "hangers" that had been hovering over parked cars

I wrapped up the work by removing epicormic sprouting caused by earlier road clearance pruning. A few weeks ago I wrote about the need to watch for this kind of follow up pruning.

All cleaned up!

A big thanks to Dennis for sticking it out when the snow started coming down hard midway through the evaluation. I'd highly recommend attending his pruning class at the Boise Public Library March 13; a presentation that will include detailed photos documenting the pruning response of Boise trees over the last 20 years 

"All About Trees" free classes begin Feb. 27. Go here for class details.

Protecting mature trees in a xeriscape conversion

Xericoasis would be a pretty stupid blog title if I wasn't at least casually interested in water conservation and zone sensitive landscape design. But the truth is, I'm getting increasingly annoyed at what I see as a "kill a tree, save the planet" attitude in a lot of xericape conversions.

It happens all the time in the urban forest of Boise's North End. Somebody decides that the Kentucky Blue grass in the front yard is sucking up too much water to be sustainable. Fair enough. But then they cap off the sprinkler system, rototill and remove the grass, install weed fabric and spread (God forbid) six yards of perma-bark over the whole area. They finish off the conversion by planting a handful of weedy looking natives and run single drip emitters to each plant.

I usually come on to the scene three to five years later when the eighty year old shade tree in their front yard starts dropping dead branches on the roof and they want an arborist to tell them why...

stressed tree in parking lot "xeriscape"

Tack isn't one of my strongest personality traits, but I do my best to politely explain to the client that:

1. the rototiller destroyed a large amount of the tree's fine water absorbing roots
2. the "perma-bark" superheats the soil
3. the weed fabric creates a hydrophobic dead zone, and,
4, the minuscule amount of water the drip line provides might keep a one gallon Eriogonum alive, but it won't do much for a tree that receives 30-60" of rainfall in its native range

Invariably, I hear the comment that that , "well maybe we shouldn't plant shade trees in our climate". Horse Puckey, I say. The benefits of our urban forest and it's role in such things as mitigating the urban heat island effect is well worth the investment of water it takes to sustain it. Besides, many properties in and around Boise are blessed with abundant non-potable irrigation water- a vestige of our valley's agrarian heritage.

Poor water coverage often seen in drip irrigation  systems

In Willowglenn installations, we often forego drip systems for a high efficiency broadcast sprinkler like Hunter's MP rotator nozzle. Efficient broadcast sprinklers more closely emulate natural rainfall, and encourage lateral root development. I've seen too many trees blown over because some genius thought that putting a bubbler at the base of tree was sufficient. It may keep the tree alive for awhile but it never develops decent lateral roots that would give it stability in the wind.

Integrating existing shade trees into a xericscape conversion can be done, but you have to be smart about it. The fact is, that 80 year old shade tree might have done OK hanging out with the turf grass, but turf grass and trees actually have quite different irrigation needs. Turf grass requires frequent watering but most trees prefer infrequent deep watering- a great starting point for the design of a mildly xeric design.

Choose an organic mulch and plant your xeriscape bed with a range of plants that provide four season interest. Take care to try and not damage the roots of your existing tree as you plant the shrubs and perennials and keep an eye on the tree for signs of stress.

How's this for an idea: let's keep our trees and save the planet. Brilliant.

Hazard pruning followup

Back in March of last year I wrote about the need for restraint when pruning mature trees. Hazard pruning is one instance where pruning a mature tree may be acceptable. Reasons for pruning might include: 

- pruning for road clearance 

- pruning away from roof shingles

- pruning away from chimneys

I was taking Christmas lights out of an enormous Rose of Sharon shrub last week when I snapped this picture of a maple tree that had been pruned for chimney clearance.

All three pruning cuts had been performed correctly and were almost entirely healed over. Looking closely though, you can see that in two out of the three branch removals, the tree has responded by sending out several epicormic shoots near each cut. Epicormic shoots lie dormant and are hormonally kept in check until damage or removal of a branch or leader occurs.

 Here's a closer look:

The first pruning cut healed over without any development of epicormic sprouting. The other two cuts have several new shoots apiece, growing right back towards the chimney, quadrupling the previous hazard.

So what's the take away? Don't forget to occasionally look up to see how the tree is reacting to pruning. Correctly pruning a tree is often not a one time event, but may need to be done over the course of several years. 


No shade tree? Blame not the sun, but yourself 
( Chinese proverb)

Overwintering an outdoor Zone 6 vertical garden

Boxwood and Heuchera 'Hercules' late November

Admittedly, this may be an answer to a question that no one has asked, but after four years of tinkering, I think vertical gardens (or vg's) can and should be a component of a zone 6 landscape design.

The first step in creating a vertical garden that will overwinter in Zone 6 is thoughtful plant selection.

I approach outdoor vg plant selection the same way I select for a standard planting composition: a combination of zone hardy, herbaceous and evergreen perennials and shrubs.

Boise may not get tremendously cold, but the dull, flat grey light of winter seems indeterminable as it drags into early "spring". As a countermeasure to the winter blahs, I make it a rule that at least half the plants I've chosen need to contribute winter interest either though dormant foliage (Pennisetum, Echinacea etc.), or evergreen or semi-evergreen foliage (Heuchera, Lamium, Hellebore, etc.). Hostas , for example, are terrific in the growing season, but they offer little in the way for winter interest.

As any gardener worth their Felcos knows, you need to select zone appropriate plants for your growing region. In horizontal applications, you have a little wiggle room; I've had pretty good luck with Zone 7 Black Mondo grass for instance. In a vertical application, you're better off sticking with a plant that is actually a zone or two hardier than what you'd normally choose.

Evergreen/semi-evergreen plants that have done well for me in a vg application include:

Boxwood (Buxus microphylla var. koreana 'Wintergreen")
Heuchera (quite a range of hardiness among the new cultivars. 'Stormy Seas' and 'Hercules' do very well.)
Winter Creeper (Euonymus fortunei)

The second (and equally important) step for successfully overwintering a vertical garden in our  Zone 6 is scheduling consistent, weekly irrigation through the winter.

Winter desiccation can be a little rough on a high desert garden but can wipe out even the toughest plants in a vertical garden.  A vg can't take advantage of winter precipitation without sophisticated rooftop water harvesting (more on that another time), so you're left to puzzle out how to get water to your vg long after your sprinklers have been winterized.

The solution I've come up with for the time being is to "t" off the 1/4" line to our ice maker behind the fridge. Once a week, if the outside temperature is at least five degrees above freezing,  I run 50' of 1/4" line out to our vg's and irrigate for about five minutes.

Oh, and try to remember to make sure the irrigation lines on your vg are free draining and no longer connected to your outside irrigation system. Frozen, busted irrigation pipes and fittings can really take the fun out of vertical gardening. Good luck...









UPDATE 12-3-13

January 2013 ended up being the 5th coldest in Boise since 1865, with temperatures 10-24 degrees lower than average. Needless to say, irrigating our vertical gardens was a bit challenging. Most of the Heuchera and the Hostas woke back up in the spring, but we lost many of our newly planted Boxwoods from the unrelenting and extremely dry cold (lack of a developed root system?).

A typical winter in Boise isn't nearly as extreme, and with occasional irrigation this is what you can typically expect over the course of 10 months:

The first photo shows the vg module in all its late summer glory: Heucheras, Hostas, Winter Creeper Euonymus, Lamium and a single Blue Star Juniper.

After a couple hard freezes in November, the herbaceous Hostas turn to jelly but the rest of the plants still look pretty good. By February though, everything but the Euonymous starts to look pretty tired and mopey (a pretty accurate description of myself in late winter).

Finally, as our northern hemisphere leans forward again to the warmth of the sun, the vertical garden comes back to life.

This year I've been working on selecting tough natives and climate adapted species that could survive through the winter with little or no care. In May I was commissioned to build my first "xeric" vertical garden.

The first pic shows the wall right after it was installed at the end of May. The second shows growth after the first six weeks. 

Hemerocallis, Nepeta, Artemisia, Yucca, Sedum and Stachys byzantina 'Helene Von Stein'.

         
Stay tuned as I'll be posting a mid-winter update to show how the vg is holding up.

Vertical garden construction at OEC

Our latest vertical gardening project is for OEC, a Boise company committed to creating dynamic, innovative and effective work spaces. Here's a mockup of how the two sided vg will look mounted to their entry desk partition:

This is the first entry of two that will photo-document the entire construction process.

Step One: Cut mineral wool batts for the 28 square foot, two sided vg

Step Two: Drill the bracket that will be used to attach the vg to the 5x5 partition post

Step Three: Attach the bracket to the 7/16 OSB vg armature

Step Four: trim bracket bolts

Step Five: Attach waterproofing vapor barrier to OSB

Step Six: Drill for 5/16 double sided mounting screws

Step Seven: Attach bolts, carriage washers and nuts

Step Ten: Carve out inclined planting chambers

Step Eleven:  Fabricate 109 emitter T's

Step Twelve: Sharpen goof plug at the base of each emitter T

Step Thirteen:  Plunge emitters into the mineral wool batts above each planting chamber

Step Fourteen: Attach transfer tubing

Step Fifteen:  Insulative Mineral Wool insulation to the attic!

Step Sixteen: Use wood glue and loose mineral wool to seal seams between batts

Step Seventeen:  Use hot glue gun to seal emitters

NEXT: Completing the OEC vertical garden...

Rare and Historic Trees

Thanks to all who weighed in for our Locate this Tree contest. This Sugar Maple is located on 8th and O’Farrell and is one of 23 trees that were included in the Boise Park System’s last (and out of print)  Rare and Historic Tree pamphlet from 1989.

We set out a few weeks ago to find how many of these trees are still with us and were pleased to find that most of the trees included in the Rare and Historic Tree pamphlet are still standing. The Sugar Maple, which will begin to dazzle us with its brilliant fall foliage in a few weeks, has recently been heavily impacted by well meaning but potentially damaging hardscape installation and incorrect pruning. The concrete patio around the base was installed at the expense of the tree’s shallow, fibrous roots which were doubtless cut and compressed for the patio base.

I’m also concerned with the recent conversion to micro-irrigation, which again, may be well intended, but probably won’t provide the broad, deep watering the tree prefers. The Perma-Bark “mulch” is also a poor choice as the rock heats up the soil and has zero water retaining capacity (find my earlier diatribe against the material here).

Finally, the pruning has been done in such a way that the tree will have a hard time healing over the wound. Proper pruning cuts need to be performed at the point where the bark branch collar terminates at the branch. This allows the cambium to quickly heal over the wound. An open, unhealed wound can become a conduit for disease and decay.

This isn't the first time this old tree has suffered abuse. The north side of the canopy has been repeatedly butchered for utility lines. We're hoping the tree takes this new round of assaults with grace and patience.

We’re committed to raising awareness of the many “heirloom” trees throughout Boise in effort to see that they are given proper care so they might be enjoyed by future generations. Stay tuned as we share some of the original trees nominated for the Rare and Historic Trees pamphlet and introduce a few notable others we've found. Contact us if you have trees that you’d like to see on this expanded list.

Vertical Gardening in Boise

In anticipation of my conversation with Charlie Woodruff of Building a Greener Idaho tomorrow on KRBX 89.9 FM, Radio Boise, I thought I'd post a series of pictures showing some of the vertical gardens we've built over the last few years. Enjoy!



Tropical Vertical Garden at Edward's Greenhouse in Boise, Idaho

Rosemary and Thyme Vertical Herb Garden

Vertical Garden on our Chicken Coop

Hosta and Heuchera Shade Vertical garden

"Industrial" Vertical garden for Lulu's Pizza

Our Office Vertical Garden

Vertical Garden Framed in Barn Wood

Lightweight Vertical Garden Module

On Display in Garden #6 of the Idaho Botanical Garden 2012 Garden Tour (Thanks to Joanne Lechner and family!)

Perma-Bark

I'm certain Dante missed a circle of Hell where wicked gardeners are forced to pick detritus out of an endless bed of PERMA-BARK®.  I got a head start on this today as I attempted to remove pine needles, leaves & strands of ornamental grass mysteriously threaded into the crushed basalt. I rate the use of this awful material in garden beds right up there with installing lead pipes for potable water & staring unblinking at the sun for pleasure.

And forget about amending the soil in your beds; once the rock "mulch" is installed, you're left with a material that dramatically heats up the ground in the summer sun, offers little in the way of water retention in the growing season or insulative protection for roots in the winter and slowly chokes the life out of trees and shrubs.

Reason enough for eternal damnation.

Just leave the damn tree alone.

Balancing myself up in the canopy of a sturdy white oak earlier this week, it occurred to me how closely arbiter and arborist are in meaning as well as spelling. In addition to the inevitable landscaping disagreements between spouses that I'm often expected to resolve, my primary job as an arborist is to somehow reconcile what the homeowner wants with what the tree wants. The homeowner wants PRUNING, and the tree, well, it just wants to be let alone.

People get it in their heads that the tree is just standing there in immobilized agony wishing it could communicate it's desire for copious pruning. Not only does the tree not want to be bothered with your surgical urgings, it'll probably flip you some serious attitude. I call it "panic epicormic sprouting" and I have personal experience. I've carefully cut off branches and have been rewarded with the emergence of five or six new branches in the same spot to deal with. That's tree attitude.

Some tree "experts" have turned this into a pretty profitable business plan. They come over to your property and prune the living hell out of the interior of your tree. Nice and tidy (arborists call this kind of damaging pruning "lion tailing"- get the visual picture?). Lucky for the "experts", the tree freaks and pushes out twice as much growth to compensate the following season.

Call it job security. Beware of the tree company that charges by the branch.

Mature trees need occasional maintenance pruning. The 5 d's are often presented as reasons to prune anytime:

1. Damaged

2. Diseased

3. Deformed

4. Dangerous

5. Dying

Prune your trees when they are young to create good structure and shape (a future blog post), but leave your mature trees unmolested by your good intentions.

Rethinking water savings in landscape design

For no other reason than to make a point, I plan to submit this recently completed front yard landscape redo in a xeriscape design contest. I'm certain the distinguished panel of judges will take a quick glance at the pictures and conclude that I obviously don't know what xeriscaping is. The entry paperwork will be tossed, er, recycled- I will get a polite note of thanks for participating in the contest, and the winner will receive acolades and praise for ripping off a High Country Garden drought tolerant design.

Or maybe I'll win because they'll have read my blog.

This handsome North End Bungalo likely started life with an equally attractive landscape. And like the Arts and Crafts style of the home, the landscape probably had a slight Asian feel. Sometime in the last 100 years somebody decided to install turf instead.

My clients moved into the home in 2009 and after I reworked the back yard, they asked if I could also help with the front. I tore out the sidewalk and the turf and replaced it with a planting scheme that by all accounts looks thirstier than the old lawn but actually offers a water savings of eighty percent.

Check out this great book on period Bungalow gardens:

Outside the Bungalow America's Arts & Crafts Garden

Saint O'Doran's Day

Saint Patrick's day is a bittersweet celebration amongst the Doran clan. It's the day we light a single candle and remember Jason O'Doran, Ireland's true hero.

While it's true Patrick drove out all the snakes from the Emerald Isle, her inhabitants were faced with the overwhelming ecological disaster of being overrun with rodents. Rodents so thick in fact, graneries were depleted & hardly a drop of Stout could be found.

In this great time of crisis O'Doran, a humble farmer and community organizer, led the people to collect what little grain was left. With it they lured the filthy creatures to an enormous vat of Stout where the vile vectors drowned. The resulting green, noxious liquid proved to be a remarkable fertilizer, and within a few months the granaries were full, the children were singing and the men resumed their happy, drunken brawling.

Alas, in the insuing year long party (and through the clever marketing efforts of Patrick's supporters), knowledge of the true events were forgotten by all but the O'Dorans themselves.

Politically Correct Plant Selection

A few years back a landscaper friend of mine sold his diesel work truck and bought a Prius. Even though the truck was more practical for his day to day work routine and actually got decent mileage, he'd been castigated by friends and clients for driving the "Beast" and felt the new hybrid would put a better polish on the image he was projecting. Coming back recently from three months of vacation, by all accounts his strategy seems to have worked.

Despite all the recently publicized problems Toyota has had recently, I like hybrids and the push to create more fuel efficient cars. During a period of the 70's that was dominated by enormous V8's, I was practically raised in the back of VW's that got triple their gas mileage. Kudos to my parents and to anyone today who wishes to conserve. What bothers me is the largely symbolic gestures businesses often make to ingratiate themselves to their customers.

I've done it myself, struggling with the symbolism of plant selection.

Here's the deal: Invasive species can have devastating effects on ecology and many invasive species were actually introduced for one reason or another. In the last twenty years I've seen the green industry become more careful in the growth and selection of plant material. Locally, for example, that means fewer Russian Olives (Elaeagnus angustifolia) are being planted. This a good thing given how the now ubiquitous invader has out-competed native species in riparian areas. But I see an unintended consequence to this elevated sense of concern: tough, drought tolerant plants are getting a bad rap in Boise because in much milder areas (e.g. San Jose, Ca) they tend to jump the fence. The truth is I've stopped using some plants in my installations not because I believe there is any danger in planting these blacklisted plants in Boise, but rather out of concern for the image I'm projecting.

I'm coming to grips with the inherent silliness of that reasoning. I finished a small commercial installation this week using, among other ornamental grasses, drifts of Nasella tenuissima. Mexican Feather Grass, as it's known by it's common name, is a wispy, somewhat ethereal grass that's the plant equivalent of mood music. It also happens to be a grass that some have called on to be banned because of its potential to become invasive. An attentive gardener employee at the location brought this to the attention of the owner and sent him a link to an online Sunset Magazine article about N. tenuissima (go here to read it). The author, Sharon Cahoon, does a great job presenting the debate, concluding that the matter of invasive potential needs to be determined regionally.

Honestly, I would be reluctant to plant N. tenuissima anywhere that receives more than 16 to 20 inches of annual rainfall but in our arid, high desert I think it's a fantastic alternative to many of the thirsty plants designers seem to use over and over (hey, I'm gonna start my own blacklist). While it's true it will self seed a little within a garden, in 20 years of digging in Boise's dirt I've never seen it wander into a neighbor's bed or naturalize into a non-irrigated area. I've heard the same debate about other plants like Euphorbia myrsinites, another tough, evergreen perennial. While I believe there should be a careful vetting process for any new introduction, designers should also be careful not to eliminate tough, drought tolerant plants from their design palette simply to appear, err, correct.

Monsanto kindly asks that you rake the forest.

Everybody has days when they realize their job is a pointless absurdity. Mine came the other day when I was raking the forest. Don't get me wrong- any kind of February work for a landscaper is a good thing, but I'm used to thinking that what I do is important. I regard landscaping as a nexus of Art and Science and often imagine myself poised heroically with a shovel in a Diego Rivera mural.

Daydreaming helps pass hours of endless raking.

On this day however, I was preoccupied with the silliness of what I was doing. A friend and long term client had taken pity on me and asked if I could squeeze in some late winter work into my busy schedule (har, har). A couple hours later I was on a little island near the Boise river raking up leaves and debris that had already begun to turn into wonderful compost over the winter. The adjacent homeowners had already cleaned their little sections of the island which just seemed to make my client's area just look, well untidy.

Cutting into this self sustaining natural system does have it's business advantages though. As an add on to my expert raking services, we also provide fertilization (which I will be sure to suggest for this little piece of Poplar and red twig dogwood riparian forest). I don't feel especially bad about it as we use organically derived, low nitrogen fertilizer but it does make think that there are probably better ways to manage our landscapes.

I'm currently working on a large community common area landscape redesign which I plan to write more about in the future. An important component of this design will be on site composting of all non-woody organic debris derived from the common area landscape. The idea is simple. Instead of hauling off the biomass, we can reduce it by a factor of ten or more through accelerated composting and reintroduce it to the beds as a nutrient rich soil conditioner. In my own landscape beds at home this has precluded the need for supplemental fertilization. This is a terrific way of emulating natural systems in an effort to create sustainable landscape maintenance .

I got the idea from raking the forest.