The Post-Apocalyptic Crevice: Urbanite Outfitters at Plant Delights/Juniper Level Botanic

The limits for crevice gardens and where they can be built are being blown away. 

This year, my research mission was to find out the reasons the Czechs and the Scots/Brits dominate the rock garden world; and one of those reasons, simply and amusingly, was availability of rock in those places.  Those folks took what they had and did amazing things.

I feel the same way about Plant Delights Nursery and Juniper Level Botanic: They are forever looking for more ways to grow more taxa to add to their existing 24,000 (yes, no kidding) and they used stacks of demo material to do it.

What’s so different about working with concrete?

Well, for one, it’s not stone.  Something I mentioned in the prior blog, and artistically something I’m still getting my head around.  Practically, it meant we could cut, break, chisel, and sledge to get peices we wanted. Jeremy was amazing at manufacturing the rough-edged but structurally-sound shapes needed to approach our very steep hill.

Jeremy, (Grounds and Research Supervisor) and Tony, owner/founder, pointed out to me that the three main components of this garden’s construciton are totally recycled.   The concrete chunks were from the driveway and barn floor of a removed building on property.  The Permatill, an expanded slate, which makes up most of the soil mix, is a cinderblock byproduct. And the compost which is layered over the open zones is made from the leaves from the nearby city of Garner, NC.

Just think: Waste products, waste products, and waste, put together to make a cutting-edge garden installation.  I’m so honored to be around for it. 

With help from Michael Peden, Jeremy and crew built the first third of crevice garden, I helped with third last week, and a third more remains to be done, literally down the road.

Let’s talk more about the mix.  Based on growth since just March in the existing beds, it’s been amazing.  Let’s call it the Schmidt mix.

The Schmidt mix:

8 parts Permatill 

1 part gravel ("#57 stone")

1/8 part  local coastal plain sand

1/8 part local Raleigh red clay

Trace parts organic matter

What’s this magic Permatill stuff? In Colorado, Expanded shale is our equivalent.  In Utah, it’s Utelite, in the UK, Seramis and in the Czech republic, baked clay. These materials are used in green roof mixes, as auto oil absorbers, kitty litter, and industrial settings like high-strength concrete.

It holds water, promotes oxygenation, and chemically holds on to and shares tons of nutrients for plants. (Jeremy would remind me that this is it’s “cation exchange capacity” for you science-heads)

We also used what I want to call the Utrecht trick.  We mixed in a bit of “clean gravel,” 1” size, to the Schmidt mix which went between urbanite layers.   Gerard Van Buiten at Utrecht in Holland told me that they mixed scoria into the soilmix which, like layer-cake icing, went in-between the layers in their crevice spheres, keeping the crevice open and preventing collapse/crushing/compaction of the soil.  

Photos of Utrecht courtesy of Jutta Arkan

Our soil using the “Utrecht Trick,” with temporary wood spacers.

Did I also mention the alkaline seep? No.  Well, we made a place for a trickle of water to dribble in, over, and steep in the concrete, creating a wet, alkaline place for plants which couldn’t even imaging a day in  the local soil’s 3.2 pH.  Jeremy Carved and chiseled channels in a few of the concrete chunks to divert the trickle of water.

Other fun things I learned with these geniuses:

Tony makes a lot of jokes in the PDN Catalogue about killing waves and waves of plants to get hardy plants or learn how to grow them.  Well, it’s not a joke!  Their successes are based on what they learn from the slaughter of a great deal of plant materials they’ve spent years growing, as well as nurturing the survivors of broad trials.

Onosma taurica from the NARGS seed exchange!

Oh yeah, plenty of plants in the first section of crevice died.  But what is alive which they could not grow before? Penstemon baccharifolius, Limonium, Goniolimon, Lithodora, Teucrium, and just about anything with silver leaves.  He is excited to grow the aroids which are found in rock rubble in the mediterranean like the elusive white form of Dracunculus vulgaris.

Jeremy’s Yucca treculeana "Sasquatch"

Jeremy taught me how using a breadknife upwards to prune out lower, dead leaves of Yucca not only can saw through the tough fibers, but the blunt end doesn’t poke/damage the base of living, healthy leaves.  

He also sold me on the idea of using rebar as a temporary, (perhaps permanent?) prop to hold up layers of our work while we were in motion.

I also had the pleasure of getting ot know Zach, their in-house Taxonomist (how cool is that?) whose golf-cart, among the fleet, certainly racks up the most miles of them all while he zips around the nursery tracking plants, their names, and their genealogy… It was surreal and dreamy to be in a place where there are real daily conversations about the marital history of agaves.

The future is bright green:

Agave montana and Allium kiiense.  (I know I will be snooping this year's seed lists for fall-blooming alliums.)

…and purple and silver…

x Mangave 'Moonglow'

Tony was excited to try Zauchneria cana as they have planted Zauchneria for years with no success.  I’m hopeful for it here.

There is no better institution better equipped to diversely populate and track and share the results of what can be grown in a crevice garden in the southeast.  Prepare to see some amazing stuff.

What is also deeply exciting is that Juniper Level is exploring for Americans, with all the reluctance of a sumo wrestler doing a cannonball into a kiddie pool, the wider universality of crevice gardening- that a concrete crevice garden can be made virtually anywhere there are people.  Now the playing field is level!  There is no excuse for any region not to be able to build crevice.  

It's timely that there is even a current article in the NARGS Quarterly by one Mr. John Beaulieu about building a backyard broken-concrete raised-bed crevice combo. (Which is also interestingly inspired by limestone cliffs and the Niagra escarpment)

(Warning: more recycling ahead)  We went all Angkor Wat/Ta Prohm to  include a rotten tree trunk here, worked into the concrete as though it had grown out of it and helped break it apart.  A little nihilist’s garden feature.

Jeremy has continued the theme.

(Last two pictures courtesy of him)

Although my heart shall always be in the mountains and desert-steppe of Colorado, what I truly love about this 

project is a new aesthetic.  It is not about mimicking natural appearances as much as mimicking natural processes.  Grasping for an intuitive logic behind this, I kept thinking 

“What would concrete look like in an abandoned city taken over by plants?”  

This is some Mad Max rock gardening.

The rusty concrete-reinforcement wire… a fossil-like relic of a time when civilization didn’t honor nature and paid a price...

Concrete Garden in Paradise: the Urbanite Crevice Garden At PDN

I woke up in a botanical garden again; this time it's real.

I'm helping out Jeremy Schmidt here at Plant Delights/Juniper Level Botanic in Raleigh, North Carolina today.

He, with help from Michael Peden of New York, built several crevice garden beds this spring, which are already planted up with crazy things.

But these crevice garden are made with "Urbanite," or broken concrete.  The brilliant gents at Utrecht Botanic have famously done this into spheres and diagonal walls, but there are few if any examples in the US.

So I'm here helping them get more of this bed finished before the NARGS AGM here November 17-19, where I thought I heard a rumour that our Panayoti will be helping  Tony Avent  peddle plants.  Ought to be awesome; Don't be a sad fool like me and miss it!

So, what are we doing?

Jeremy and friends already started; so there is an established look, motifs, etcetera, that anything I do ought to compliment.  I don't see my visit here as shoe-horning yet another ("my") style onto the grounds as much as seeing what they've started, and then extrapolate from that flavor to fill a larger, challenging area.   Here's what PDN has done so far:


The first section are in divided beds on a corner.



Ooo, look, it's Agave montana in a crevice garden. I could faint with delight.  You know, tons (most?) agaves are crevice plants out in the wild.

Crevices aren't totally new at PDN- here, Bommeria hispida from AZ colonizing a drystacked sandstone wall gloriously.




Zach, their in-house taxonomist, says Teucrium polium was the plant whose surprising success seemed most due to life in a crevice.  


The concrete color has already aged warmly since this spring when the first section went in..

So I landed here and am trying to absorb the spirit of this thing.

Concrete is not rock. It's funny, because none of us can help ourselves from calling it "rock" or "stone" as we work with it.  But it isn't.  All the cerebral and intuitive attitudes I have about placing stone is just baggage here.  This is a garden which intends to be a garden- and as much as it may give a little nod to natural rock outcrops  (in this case, Jeremy had the Canadian Shield in mind), it is only a nod, and cannot possible try to replicate or mimic rock, because it isn't.   So we shouldn't.



Yes,  it's a sculpture, an artifact, a garden installation.  It's human-made.


So creating regular- two-by-four width spaced crevices is fair game.  When starting my fanned/fluted section, I used two-by-four lumber's different dimensions to vary the crevices...
Props to Jeremy for the two-by-four idea.

Some of the native beach sand soil we are cutting into is madly beautiful.

Instead of fossils, there are rusty shadows of wire reinforcements.  There is no strata, just the relentless one-flat-sided nature of concrete which was once one big flat thing.  So you shouldn't fight that to fake a mountain.  I believe.


That's also why it doesn't bother me at all that the cold dark gray Permatil (expanded shale) de facto topdressing absolutely contrasts to the warm white- gray concrete.  Especially when there are Mammillaria plumosa. (Yeah, that's a total gambit)

So this crevice garden must honor its material, which is the broken up foundation of an old razed barn.  At its core it is doing something great- cultivating rare plants- with something nasty- human leftover waste-materials.  It a little Tyler Durden, a little Hugelkultur, and totally contrived. And we're running with it.

Coming to you, from a place totally infested with Agave ovatifolia.  Collect them all.

A Plant has a Name

One of the three most inquired-after plants at APEX has been this Hedysarum, which I had failed to record, and assumed was a plant from Sunscapes.  Although many are, it is not:

Hedysarum dshambulicum came via Mike Bone at Denver Botanic from a collecting trip of his.

Now we know!

A Workhorse is finally put to Work: Alkali Sacaton

Sporobolus airoides, a grass in light pink bloom, gives a mist the San Luis Valley between gnarly green greasewood.

It's my favorite grass of all time, and this is getting worse all the time when it keep proving to work in so many places where others fail.

Sporobolus airoides is the Alkali Dropseed, or Alkali Sacaton; the dry western version of the beloved Prairie Dropseed, Sporobolus heterolepis. It is also closely related to the Giant Sacaton, Sporobolus wrightii,  both of which are very different creatures than this.

Pros:
Can grow in wet places which flood/ get wet
Can grow in dry places with zero irrigation and 9" of natural rain.
Does not spread by rhizomes
Does not spread by seed (totally strange, as it's easy to intentionally grow from seed)
Lives a long time (so many grasses die out or at least the center dies)
Seems to combat weeds (I started to notice this year and am testing it further)
Grows fine in extreme saline/alkaline soils.  It's in the name.

Cons:
Some of the dried flower panicles may blow and tumble around in winter.  That's it.


In leaf, it's a fine textured grass knee-high, and the flower stems, emerging in mid-summer, are hip-high.  (Note the taller plant at back right- this is a giant sacaton, S. wrightii, for comparison.

As such an ideal plant, I wondered why it was almost never used in common landscaping.  I have planted or spec'd thousands in the last few years in my own landscape work.  But hooray! I am not alone as I have seen it in medians in Ft. Collins, and now-

Holy wow, there are some in a streetscape on South Broadway in Denver, and other-wow, I didn't plant them.


It does a fine job at catching the light for months and distracting you from the boringness of suburbity.

It is available from Chelsea Nursery in Grand Junction, somebody in Northern Colorado, and I (at Paintbrush Gardens) specialty grow it for our designs.

The self-caging Buckwheat who loves a view

At a distance, and from the wrong angle, Eriogonum heermannii (var. sulcatum here) is an ugly scrapper of a native.  You may first notice it by pricking yourself when scrambling up a slope to look at something more obvious, like that Penstemon petiolatus above.

Eriogonum heermanii v. sulcatum in a dry rock garden with Inula verbascifolia, etc.

But this fantastic woody buckwheat has a small cult following of rock gardeners.

It's the inflorescences- like barbed wire studded with pearls of flowers- which grow and branch and layer on the outside of last year's growth, while the modest leaves are produced safely on the inside.

Eriogonum heermannii

Overlooking Marble Canyon (above the Grand Canyon)

You will find it in and around the Mojave desert in rocky places, and I've never seen it not sitting directly on or in cracks of limestone.

Our friend, Susan-in-the- NARGS- hat among Petrophytum caespitosum and E. heermannii From our botanizing trip in November 2016 on the NV/UT border; thanks for taking us there, Susan.

The attraction to this plant is not purely in form, but winter color, too.

Is it a garden plant?  Not Enough!

 I look forward to trying it unirrigated, as it seems a likely candidate and is just getting better with age in my monthly-watered clay-bottom rockery.  Mine was a glorious little desert puff cloud of flowers during the peak heat of summer throughout August.

Where can you get it?    At least three ways: 

1. Go camping in the mojave in winter, or 

2. By joining the Eriogonum Society and requesting seed (eriogonums are generally very easy where rock garden seed is concerned) or 

3. From Alplains, whose description of it must be quoted; remember he has been a professional plant hunter in America for decades:

"My vote for the most bizarre member of this genus... interwoven zig-zag stems... turning bright rust colors as they age."

-Alan Bradshaw