The Vertivore's Edible Green Wall

If I was to draw a Venn diagram showing the overlap of my gardening and landscape interests, you'd probably find edible green walls smack in the center, next to medieval Japanese stonework and my fig tree.

Oh look, I did.

Up to this point I've mostly written about green walls as an ornamental element, but vertical space is also a terrific place to grow an edible garden. My long term goal for our own property is to place an edible component within three or four steps anywhere on our acre. We're lucky to have so much room, but with the continuing trend of urbanization and smaller lots, many people don't have the room to grow greens and veggies conventionally. But if you've got a wall, there's a way.

Skyfarm: Gordan Graff

Optimistic futurists love to present us with images of a biophilic, urban paradise not too far away.  Heavy on stunning visuals and light on actual details, this hazy vision usually includes rendered images of urban agriculture on the walls and rooftops of the city skyline.

Part of a larger concept called Agriculture 2.0, this discussion of urban of food production rarely takes into consideration some of the problems that need to be solved to make this vision real.

Soil based green wall systems, for example, are very heavy, requiring serious engineering for the support armature.  GLTi's 2,380 square-foot living wall in Pittsburg has an estimated weight of 24 tons when fully saturated. Some have even described this kind of urban farming as financially nonsensical.*

Personally, I think it makes a lot of sense, if the design challenges can be addressed. To that end I started experimenting a few years back (successfully, I might add) with a lightweight mineral wool system.

So far, we've grown nasturtiums, chard, tomatoes and dozens of varieties of herbs including rosemary, thyme, sage, mint, basil and oregano.

This year I plan to try out collard greens, rainbow chard, spinach, rapini and cabbage.

Rest assured I'll be sharing pictures of our edible green wall through the season.


*But the author seems to have some internal conflict on the matter as demonstrated by this article.

How To Prevent Your Tree From Falling Over

Far too many Boise trees blow over during relatively light wind storms. It's in the tree's best interest not to perform a faceplant, so why does it happen so often?

Based on years of post mortem evaluation, Jason shares tips on how to prevent your tree from falling over. Head on over to the D&B Supply blog for more.

~Stacy

Dem Bones ... The Importance of Scale and Style in Hardscape Construction

I've yet to be involved in a project where the home and the landscape are designed at the same time (does that even happen anymore?). Generally, I'm given a completed plan view of a house perched on abstract topography. This is my opportunity to get the bones of the landscape right the first time around.

What do I mean by that? Most of our installation projects consist of improving existing landscapes. Often this involves adjusting the scale and style of the hardscape components of the landscape (things like patios and walkways), to compliment the scale and style of the home; details that should have been considered the first time around.

I'm astonished at the amount of effort and creativity in home design that promptly stops at the outside edge of the home, but you certainly won't find me complaining. Every undersized 4' x 8' patio paired with a 4000 sq. foot house is just another project in waiting.

Here's the plan I originally received for a job we're currently working on.

Deliciously blank.

Later the architect gave me an updated plan showing the driveway sweep and proposed entrance walkway (floating rectangles that somehow resolve the 5 foot elevation difference between the driveway and the front door).

This thumbnail sketch of my counter proposal for the entrance walkway reveals a less direct route to the front door. This is where I am trying to set the cadence and tone for the entire landscape, taking cues from the architecture and style of the home. (Read: creating the illusion that the home and landscape were actually designed in thoughtful tandem.)







Home construction delays put this project so far out that I'd nearly forgotten about it, but following a break in the cold weather, the entrance walkway was finally installed last month.

There's quite a bit of work yet to do (for example, covenant restrictions require all vertical surfaces to be natural stone, cultured stone or stucco), but it's gratifying to see a harmonious setting for this magnificent home finally begin to materialize.

Updates to follow (more hardscape and then here come the plants!) ...

10 Mile Interchange Hellstrip

Fitter, happier

Am I the only one who finds this repeating motif on the new(ish) Ten Mile Interchange just a bit creepy?

Aside from the undertones of Orwellian Maoist thought control, The Ten Mile Road Interchange in Meridian, Idaho represents a subtle change in public works projects around Ada County. Gone are the days of shoulder to shoulder asphalt and concrete. Honest to goodness, live plant material and permeable surfaces are beginning to be incorporated into new design.

But, as I was often reminded as a child, they don't give you a medal for good intentions, so let's perform some taxpayer deconstruction of the project.

PLANTS

Behold, an Idaho winter: a washed out/monochromatic sky meets a washed out/monochromatic planting bed.

What? I'm not being fair because it's February? While it is true that last summer there was a lovely succession of color here, compliments of Echinacea purpurea, Coreopsis verticillata, Perovskia atriplicifolia, Gaillardia, and Leucanthemum x superbum, they are all now distant herbaceous memories from a half forgotten warm season.





Winter "structure" is mostly provided now by the skeletons of miniature Berberis, the carcasses of winter kill Lavendula, prematurely trimmed ornamental grasses, and the much maligned Yucca filamentosa.

(Incidentally, I swear I will punch the next person who tells me that "there's a reason they call them YUCKas". I mean, cut them a little slack, they are the only plants in this bed providing any real color for five months of the year!)

I think lavender is great and I probably overuse it in my designs, but what is there not to like? It's mildly drought tolerant, the bees love it, it smells terrific and it blooms for months.

There are plenty of varieties of  lavender that are dependably hardy in our area, but I'll be surprised if even half the lavender in these beds wake up in the spring. They really don't catch a break between the basalt "mulch" heat sink in the summer and snow plows and drunk drivers in the winter.

Which leads us to...


MULCH/HARDSCAPE

Un-shaded asphalt surfaces can reach temperatures as high as 160 degrees. A planting bed surrounded on all sides by asphalt and concrete receives a tremendous amount of this as reflective heat. What is the logic of using dark, basalt mulch in the beds to further heat up the poor plants?

Crushed basalt is also a nightmare to maintain.




Another observation: the median beds are elevated, surrounded by slope faced curbs. Perhaps a better approach would have been to match the planting grade with that of the road and install curb cuts for passive rain harvesting?

IRRIGATION

The purple cap on the popup gives us the heads up that non-potable water is being used. In many areas of the country that means reclaimed, grey water with potential problems associated with salt build up. Not here. Snow melt is what built Boise and our urban forest and I'm so pleased to see it being used in place of domestic water.

As a card carrying member of the "green industry" I'm expected to hate broadcast sprayers and embrace drip lines and micro-irrigation, but too often micro-irrigation = dead plants. This is partially due to incorrect installation (single emitters rather than grid installation), but also because our soil has lousy capillary action resulting in uneven distribution of water and poor root development.


CONCLUSION

There's a lot to like about this project- for about 8 months of the year anyway. Swapping out even half of the standard army-green Yucca filamentosa with a variegated form (Yucca filamentosa 'Bright Edge' or 'Color Guard'), or the bluish Yucca rostrata would give this planting a lot more punch during our indeterminable "gray season".

The damaged lavender along the edges of the median strip should probably be replaced with a tougher, semi-evergreen perennial that can take the heat and drive-over damage; maybe Penstemon pinifolius or Arenaria 'Wallowa Mountains'?

Since I'm feeling generous, I'll say that the crushed basalt "mulch" is slightly better than paving over a garden bed.  I'd really like to see an organic mulch installed (or at least light colored, porous sandstone if you must have rock). I'm sure the crushed basalt was installed out of an assumption that an organic mulch would blow out onto the street and the rock would stay put. You can see how well that's working.

Yucca rostrata in Turf

photo credit: Ocean Blue

Here's a little advice: if you see a garden you like, take a picture of it today because it might be gone tomorrow. This was the case with a terrific xeriscape installed along lower Fairview Avenue in Boise five or six years ago.

Framed by two specimen sized Yucca rostrata, the unknown landscaper nailed it with a beautiful composition that wasn't quite riotous cottage garden style nor an uptight, rectilinear, modernist's garden- but rather a pitch perfect hybrid of the two. Hesperalo parvifolia, Agastache, Muhlenbergia and a half dozen other plant varieties I can't remember were combined with three triangulated, lichen covered boulders. Before I was able to take a photo (those were, after all, the days before decent cell phone cameras) all but the Yucca rostrata had been ripped out.

In it's place, someone decided to plant turf, and because the new business was an artsy, graphic design firm, a token Cor-ten weathered planter was installed with a crisp line of Equisetum.

I blame the turf indirectly on the Japanese architect, Tadao Ando and his preoccupation with horizontal planes. Many (most?) of his buildings sit at right angles to a plane of water or turf grass.

Photo courtesy of the Clark Institute

Photo credit:  Tomas Riehle 2004

Clean, calming, serene? Sure. Sustainable? Maybe in Kentucky. Never the less, this informs the aesthetic sensibilities of a great number of people I know personally in the creative fields. These are decent people who recycle, bike to work and support their local farmer (and landscaper) but can't let go of their favorite monoculture.

But back to the landscape and the Yucca rostrata...

Here's how the makeover looked a year or so after the turf/Cor-ten was installed in place of the xeriscape.

Photo credit: Google street view September 2011

I was pretty convinced that the Yucca rostrata would be dead by year's end. After all, the irrigation needs of turf grass and yuccas don't typically parallel. I'm pleased to report I was dead wrong.

Both have grown at least two feet in the last two and a half years.

 

No sign of my other prediction: string trimmer damage to the trunk.

While I wish the original xeriscape had been left in place, I'm pleased the specimen size Yucca rostrata are doing so well. I'll be employing Yucca rostrata in several installations in 2014.

Spring Care of Ornamental Grasses

Wondering how and when to trim those ornamental grasses?  

Pop over to the D&B Supply blog for Jason's tutorial.  

~Stacy

Tracking the Natural Range of Trees by Annual Precipitation Rates

When I started preparing for my 2014 tree care presentations earlier this year, I realized I needed to rework one of the most important parts: explaining why irrigation is so important for Boise's urban forest. Many folks simply cannot grasp that the vast majority of these trees would not be here without supplemental water (whether or not this is sustainable, good, bad or meaningless is a rich topic for a future blog).

I blame this on the suspiciously apocryphal story of how Boise got it's name. It goes something like this: French fur traders exclaimed "Les Bois!" as they crested over a rise and saw the poplar lined Boise river below. When I hear this I can't stop imagining Herve Villechaize in a bearskin cloak, shouting "De trees! De trees!

My presentation strategy this year is to shock and awe my audience with a spread sheet. That's right, I'm going to Blind Them With Science! 

The idea is pretty straight forward. Most of the trees in our urban forest are native to the hardwood forests of the eastern Unites States. Those forests start to disappear past the Mississippi right along a magical line of demarcation where the precipitation drops below 20 inches a year. Here are the facts of life: Mountain Home gets an average of 7.62" of precipitation, Meridian gets 10.94", Boise 11.73". No water. No trees. *

Growing up first as a Marine Corp brat and then later a Forest Service brat, our family slowly moved westward from North Carolina, to Indiana, on to North Dakota and then zig-zagged across the basin and range interior west. It was a slow motion lesson in how precipitation shapes ecology.

For my presentation, I speed up this lesson by picking a common shade tree, the Silver Maple, and track it's natural range. By finding the western edge of the range and comparing that to the annual precipitation of that edge, we can infer the low end of the Silver Maple's annual water needs.

So why just pick a couple data points? I decided to find towns and cities with the highest and lowest precipitation in every state (courtesy of weatherDB). The data backs up what we know to be true, that is, precipitation begins to taper off in Nebraska, Minnesota, Kansas and Oklahoma. West Mineral in eastern Kansas, for instance, has an annual precipitation rate of 46.89", while Coolidge on the far western edge gets 16.82".

So take a look at the numbers. Basin and range topography starts to mess with the gradual decrease in precipitation as you move west**, and there are a couple unexpected anomalies (what's with Bell City, Louisiana 30 miles from the Gulf of Mexico?), but the numbers support my assertion that an urban forest in the arid west composed primarily of eastern hardwoods is by definition an artificial construct, albeit a beautiful one.

	Alabama		13.54” (Jones)	70.73” (Brooklyn)
	Alaska		3.8” (Prudhoe Bay)	156” (Whittier)
	Arizona		3.3” (Yuma)	23.91” (Superior)
	Arkansas		41.83” (Peel)	58.82” (Sulphur Springs)
	California		2.85” (Anza)	84.36” (Smith River)
	Colorado		7.04” (Monte Vista)	30.82” (Idaho Springs)
	Connecticut		42.74” (Bridgeport)	58.83” (West Hartford)
	Delaware		41.59” (Little Creek)	45.91” (Cheswold)
	Florida		42.97” (Salem)	70.73” (Century)
	Georgia		43.57” (Keysville)	80.96” (Pine Mountain)
	Hawaii		11.96” (Kailua Kona)	240.02” (Volcano)
	Idaho		7.62” (Mountain Home)	42.43” (Elk River)
	Illinois		33.35” (Arlington Hills)	50.21” (Joppa)
	Indiana		36.58” (Buck Creek)	51.17” (Rome)
	Iowa		26.38” (Larchwood)	40.91” (Russell)
	Kansas		16.82” (Coolidge)	46.89” (West Mineral)
	Kentucky		38.64” (Flatwoods)	57.73” (Cosplint)
	Louisiana		14.93” (Bell City)	67.26” (St. Bernard)
	Maine		33.6” (Saint Agatha)	56.72” (Cherryfield)
	Maryland		37.36” (Flintstone)	50.2” (Oakland)
	Massachusetts		42.55” (Orange)	53.42” (Avon)
	Michigan		41.14” (Lacota)	23.82” (Iron Mountain)
	Minnesota		20.65” (Kennedy)	36.5” (Whalan)
	Mississippi		50.22” (Lake Cormorant)	68.88” (Wiggins)
	Missouri		33.57” (Mound City)	52.26” (Lesterville)
	Montana		7.2” (Red Lodge)	37.96” (Saltese)
	Nebraska		14.21” (Henry)	34.84” (Douglas)
	Nevada		3.66” (Luning)	23.74” (Glenbrook)
	New Hampshire		38.03” (Plainfield)	98.87” (Randolph)
	New Jersey		40.01” (Ocean City)	52.39” (Dover)
	New Mexico		8.28” (Sanostee)	30.28” (Mescalero)
	New York		30.8” (Springwater)	62.69” (Bearsville)
	North Carolina		39.96” (Wagram)	90.51” (Balsam Grove)
	North Dakota		13.98” (Grenora)	25.2” (Abercrombie)
	Ohio		31.48” (Farmer)	47.71” (Harrison)
	Oklahoma		15.79” (Felt)	56.14” (Broken Bow)
	Oregon		8.92” (Boardman)	122.28” (Depoe Bay)
	Pennsylvania		33.05” (Tioga)	54.21” (Brownfield)
	Rhode Island		43.58” (Block Island)	51.42” (Smithfield)
	South Carolina		39.96” (Tatum)	80.96” (Mountain Rest)
	South Dakota		14.52” (Ludlow)	31.34” (Jefferson)
	Tennessee		73.49” (Gatlinburg)	41.01” (Kingsport)
	Texas		8.93” (Fort Hancock)	64.2” (Orange)
	Utah		5.23” (Monument Valley)	34.42” (Brian Head)
	Vermont		33.64” (North Hero)	55.84” (Manchester)
	Virginia		35.28” (Timberville)	52.78” (Tyro)
	Washington		7.42” (Royal City)	115.62” (Amanda Park)
	West Virginia		33.02” (Kirby)	59.87” (Snowshoe)
	Wisconsin		23.82” (Dunbar)	37.86” (Belmont)
	Wyoming		6.48” (Big Piney)	22.11” (Moose)

*OK, that's a bit too simplistic. We do have riparian trees that cling to the banks of our waterways like a mercy seat, but the only native, non-riparian, deciduous tree in our area is the shrubby, brutish Celtis reticulata.

**Idaho City, for example, is 36 miles northeast and 1200 feet higher than Boise and receives 27.95" of precip. compared to Boise at 11.73".