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

Cheyenne: Finishing touches to the Unfinished

Nature is the real boss here.

Monday's snow turned the surrounding topsoil to mud, halting my finishing the last rock bits. But that's OK, because this fall was an opportune if unplanned time to jam in the first plants!

 Yeah, "jamming" is what we young people will call planting from now on.

That's my jam.

The back bit, hidden against the building, will sit undone till next spring, but you'll see the little childsplay-river rivulet back there where I tested the grade and drainage so that snowmelt crashing off the glass roof can drain over the surface of a potentially frozen soil and escape from around the crevice garden.  You've gotta plan for this stuff unless your bad dreams aren't made of boulders, ice, snow, and cracking, like a season finale of Game of Thrones.

One of the great fortunes of this project is having access to not just gravel made out of the very stone we used, but different screened sizes, too.  So we did that thing which makes quarries and rock-shops raised their eyebrows: buy several different sizes and let them get mixed in the truck.

A bit of fun- they sort themselves again in a wheelbarrow if tipped just right.

As per my usual approach, the whole garden got topressed in an inch or two thick of 1/4" screen gravel (easy to dig into), which gives the look of a very steep and convoluted parking lot in-between all the big stones.  But that is what the odd sized gravel is for: "Nature-ifying." (in the spirit of stupid invented words)

An open-soil expanse to give foil to and break up the solid-stone areas.  

Let's have a look at the progress of Nature-ifying an area of flat, even gravel:

Flat, even gravel with a few outliers from the solid-stone areas.

Larger (1" - 1.5", or  2.5 - 4cm) gravel added unevenly: heavy in some areas, absent in others.

Stepped on. The faces of each gravel piece rock looks up now, which often happens on its own after a good winter. But the keen eye will see there is still a gap in size between the softball-sized chunks and the largest gravel.

So we throw in just a few, literally 3, which bridge that size.

Bang, done: "Naturified." Now we have to patiently let the plants grow up, for which we have no Millennial-generation shortcut.

Have I mentioned the pyrite, or "fool's gold." which is very visible on some of the stone's surfaces?  It's a conspiracy between sulfur and iron.

I learned a lot from the master gardeners: what they were growing in their gardens (and how it behaves), which will inform what plants I try next spring.

And I was also told what I'd sought to no avail- the name of this geologic member- 

"Sherman Granite."

Bare-rooting is the only way to plant manzanitas.   And in fall, too.

Beautifully grown by Kelly Grummons, this is our favorite, the Greenleaf Manzanita, Arctostaphylos patula, which certainly must occur in a certain rare corner of Wyoming.  This particular strain is a 2011 Utah collection by the Boulder, CO plantsman Allen Taylor.  

As I wrote earlier- here is how to know you are planting at the ideal time.  Roots in active growth! Look at'm grow!  They are preserved by a patient, gentle washing in bucket of water to get the potting mix mostly off.  We won't cry if there is a little bit of perlite clinging in still.

They don't look too bad against that stone.   I put them in this "ravine" to protect them, while young, from wind, and I'm curious how far out they will grow once settled in.  I've seen them hunkered down behind rocks in nature when on windy ridges.   They are not just here because I love manzanitas.  Well, in part.  Actually, they lend a good, rich green to the garden, visible from a distance. The sexy sexy rutile-red stems against the blue-purple granite is just a bonus.

Rhamnus pumila, a dwarf alpine buckthorn from the Alps, is promising for some amazing gnarled woody structure as well as, again, a supply of rich green, very visible at a distance (and useful aesthetically in this way).  I also feel that because it is deciduous, it will not suffer from the drying winter winds.  I'll let you know. 

It's one of my favorite plants going in.  There are three, and long-term hopes are that there will be both a boy and girl in that mix so that future mad plant fiends will be able to collect the fruit and grow more of them. Tell me: is there any real reason not to get plant-randy by a tiny tree which espaliers itself in limestone crevices?  Ooof!

Well, there is a bit of warm fall weather ahead, perhaps enough to let everything root in well before proper cold and winter.  I look forward to coming back and seeing you all in spring and finishing the garden.

Cheyenne: Why don't we add another?

The stones are fine from the front, the first viewing people will see.

Behind the garden (upper right) we see the catwalk leading to the old solar production house under renovation (upper left.)

Yeah, the front is fine.

But the area behind it abruptly becomes open soil/no rocks/future garden along the west face of the conservatory.  Note the stockpile of stone on the mid-right, crevice garden on far right, lumber in-between.

 

We piled up the rest of the rocks next to the unfinished garden so it would be close for me to grab from.  And I had a look at the garden from this angle, seen from that second-story catwalk.

But a new lesson emerged from just seeing the stock pile. (Susan Sims noted that observing how stones land when just dumped helps understand how they want to fit together)

This lesson here is just that the garden looks much more integrated into the bed/soil/path when the presence/volume of rock continues, dribbles away if you will, to that open bed, past the corner of the building.  The Crevice Garden's profile, generally, too, looks better with this "extension."  A hard, basically strait-edged boundary of the crevice garden at the building corner (incidentally marked with lumber here) was about to look very rigid, very formal and fake.  Instead, crevice invades perennial bed and perennial bed invades crevice bed, like the black and white dots in the yin-yang symbol.  A nice way to marry to very different surfaces of garden.  I wish I could take credit for that idea, but it was an accident of where a pile of rocks landed.

Now, upon that little revelation, next spring I have to exhume and then arrange those stockpile stones right where they sit.  Having the ability to make little changes in direction when opportunities arise has made the crevice garden at Cheyenne botanic one of my favorite projects of all time.

(An Agastache which came up in the botanic's compost heap was mercifully spared the snow/frost and brought into the staff breakroom; a delight to see when I came in to raid the coffeepot.)

Cheyenne: Master Gardeners to the Rescue

First, I did a little talk on Crevice garden history and examples around the world...

(photo courtesy of Shane Smith)

Then, we looked at the one here at the entry of the gardens, talked about its inception, which is mostly documented here on the blog...

And we talked bare-root-planting, which the Master Gardeners took to with finesse, helping me get most of the plants in the ground today, alleviating my worries about future cold weather.

The Master Gardeners must also be given credit for providing the grant which made this whole dang thing possible.  My thanks to them for this exciting opportunity, adding another stone in the crown of the Cheyenne Botanic.

Manzanita fans will be interested to know that I planted several here, and that today, on October the 3rd, the plants grown in pots were sending out phenomenally fast root growth; long, white to translucent extensions...  The ideal time to plant a plant is when it's internal clock says  "Roooooooot!"

So as to not break off too many of these finer roots, I delicately washed away the soil from the Manzanitas in a five gallon bucket to plant them and cover them with shade cloth for their first winter. It worked really well at APEX, so I'm doing it here.

250 plants at present, 101 species.  And this is just he first planting of 1/4 of the target plants...

Cheyenne Botanic: Man Proposes.