Thursday, September 3, 2020

The Art of an Annex: Crevice Innovation in New Zealand

 I told you so. 

That the New Zealand rock gardeners would take crevice gardens into their own hands and innovate right away. While I was there, we did make plans for an extension of the crevice garden to span across the main path from its main seat in the heather garden to include a corner of the main rock garden which needed renovating anyhow, so we rationed some stone for that future project.

My friend Hamish sent me these pictures of what they recently did, and I'd like to point out some specifics of good art in its design, and some opinions of mine. All photos are his. There is a thorough write-up that recently came out in the printed NZAGS bulletin on the project. 

They've also put out a really great "How to make a small crevice garden" brochure, something the world really needed (and why I hadn't done it already? I'm an idiot.) 

So, this is the main Crevice Garden at the Christchurch botanic- the new annex is visible in the background next to the blue figure. (Looks like they've got some temporary ropes to keep folks off the bed- I've seen this so often that a new crevice garden is climbing-candy until plants have well grown and make it obvious that it's not a toy!)

New annex in foreground, main installation in back.

What I wanted to discuss was this.  Notice how it is :

1. Oriented with the "strata" of the other garden.
2. the Annex is a massive shape that is about the same size and form as the big historic stones
3. The flat-topped stones in the path follow the logic...

Now the path treatment is what I wanted to get editorial about. I love this. 

There has long been discussion on the ZZ-style of setting stones in the path through a crevice garden, oriented with the strata, but whose tops are flat for good foot use. The idea is that it looks like a human roadcut has been made through solid stone. It also offers great stability, adding a solid "footing" for rocks that make the base of the garden.  It's also super useful as steps within a sloping crevice garden. It was my favorite part of my last Vail project, in fact.

I agree with the concept, but what has bothered me is that it often appears in places that meet otherwise naturalistic, eroded-looking faces that "return" to the ground. And I would argue that in nature, an eroded cliff face like that dives underground and is buried by soil, not by mechanically cut rock surfaces. I've never liked where a nice crevice cliff meets a flat-creviced path. If a cliff did meet a cut path, then by that logic, the vertical cliff, too, would have been clean-cut (and in the few gardens where I've done this, that is how I treated it).  Basically I feel that the path paved with stones is cute, and in-keeping, but not strictly really natural or necessarily artistic. If it were, it would have irregularity or some cue that it, too, is a naturalistic stone, rather than a novel patio paving that sort-of matches the rock garden. It usually looks to me like there were leftover rocks that needed disposal. 

BUT, here is where it works for me.  And very well. Here, the natural cliffs return to the ground and it meets gravel chipped surface,  suggesting the rest of the form is buried underground, but where we see the path-grade flat crevice surface, it look every bit like it was a solid mass- that was cut for the path.  It's even the shape of a big sliver of rock. I love this so much. It's so well done.  What is more (bonus art points as far as I'm concerned) it functions in the design of the garden as an eye-catch for the passerby on that wide main path who is looking at the ground and cruising through the park on their way to work. (Wide/strait paths lend themselves to fast walking)   It catches the ground-level eye and draws a shoe-staring viewer to look at the garden that flanks them welcomely.  I love it. 

We're going to have to get to work, and hard! - the New Zealanders are putting us to shame!

Wednesday, August 26, 2020

The Prickly Thrift seed problem


Acantholimon caesarium, sold by Arrowhead Alpines and growing at APEX.

As a drooling young rock gardener, I was told time and time again by the old timers that Acantholimon seed was always 95% empty, infertile seed, for some mysterious reason. I even saw a botanical illustration once that pointed to the dried out flower and called it the seed. Everyone has a story about it: never growing from seed they got from exchanges, only growing from certain czech seed hunters' seed, et cetera.  And everyone had a different explanation for why they were rare from seed, leaving most to be grown from cuttings. And yet you'd see the odd seed volunteer plant appearing here and there in folks' gardens.

(Soft pink flowers of Acantholimon armenum are gracefully replaced by similar white clayx which are generously full of lies and disappointment. None of these have been fertile, ever.)

Fifteen years later:

I've beat my head into this wall for long enough to share this:

Some plants produce mostly good seed, others none. Most produce little.  I expect it is a pollination thing- is there a bug with the right sized lips or tongue or whatever to do the deed? When I looked into it, I found just one paper in turkish about sweat bees pollinating them, but at APEX, Acantholimon halophilum is covered with mostly honeybees and a few others. Those plants usually produce loads of good seed, last year was an exception. Also, perhaps importantly, it may be necessary for there to be more than one lonesome-george plant so they can pollinate one another. This is conjecture. 

Whatever the case, the good news is this: you can check and see if seed is viable- with a plump embryo and endosperm. You need a pudgy parachute. Rumour and oral history says a czech seed hunter used the term "pregnant ballerinas" to describe the look of a good seed. It's just visible. But even better, just smush off the papery calyx from the seed and see if it has the goods:

A thing that looks the size, shape, and color of a black rice grain. Now you know.  I wish I'd known years ago.

Acantholimon seed. See two good ones and something that isn't, on the left. On the right, three familiar entire seed contraptions- two look full and promising and the middle/lower one looks empty.  

That's it.

Thanks to Mike Bone at DBG for being the last person I bugged about this and confirming what I thought I'd figured out.

Now you can grow out sweet little pots of seedlings like Bill Adams' in the picture, or avoid empty pots resulting from empty seed.

Seven Recipes for Baking your Ornamental Fescues

 Do you love ornamental fescues? The garden varieties are wonderful little clumps of evergreen softness. They seem like the perfect entourage for any meadow plants, and I’m really into meadows right now. So I need that. Like a sweet tooth.

But I’ve long observed large commercial plantings of Festuca ‘Boulder Blue’ and his brothers just die off after a few years- they just don’t seem to live very long, especially down here in a hot desert valley. It seems they do better in the mountain towns of Colorado, and even Denver and Fort Collins. But I cannot live without some fescue action. Lots of it. So here let me share what I’ve learned about them. For reference, all of these I'm comparing are irrigated once a week in summer, less in spring/fall, no exceptions. Here are the seven taxa I’ve tried in this oven we call the Grand Valley:

Festuca ovina

Festuca arizonica

Festuca saximontana

Festuca amethystina

Festuca glauca 'Beyond Blue'

Festuca mairei

Festica ovina ‘Eiler’s Beauty’

Festuca ovina seems to do well with dryness and part shade. Its seed is cheap. It has a lovely delicate stature just under a foot. I was even a star performer in unwatered landscapes in their first year. But year 2 or 3.... POOF!  Gone. It doesn't replace itself with seedlings reliably enough for that not to be a serious problem. In the mountains it has been a stalwart weed suppressor and living for years and years.

This is Festuca saximontata, seed grown, at its best year two. It's being useful inside the compost bin about now. The thing is, Grand Junction, I believe, crosses a threshold of heat that is just too much for some plants. If it does not outright kill them, it slows them way down, keeps them from ever amounting to much, or slams the gas pedal down on their aging process. 
This species might be the worst one for dying young in this climate.

"Dry" in the mountains means something different than "dry" down here when it is 100F (38C) for weeks, and no rain for months.  And I am certain plants notice. 

It's easy to get Festuca amethystina  mixed up with ovina; but this one has a certain purple cast to the leaves. It's still in its youth, so I'm avoiding a love affair with it until it proves itself. I do like the sparser blooming so that colorful neighboring flowers or its own rich leaves are not hidden.
Say a little prayer for the lifespan of tufted fescue.

But lo! Who is this handsome beast!?

Who is this generous fountain of flower, this urgent urchin, this dense denizen, this total rockstar?   This is a selection of Festuca ovina from Turkey called 'Eiler's Beauty.'  

Just compare 'Eiler's Beauty' (left) to a regular sheep fescue Festuca ovina (right).  So much flower power.
So far, this guy has not died yet.  It's now two years past the cutoff point that throws the others in the bodybag. I really hope it keeps going. If it dies at seven years, I think I'll be OK with that.

Its smallness has made it my first grass to trial as a steppe garden/rock garden transition grass, because it can cast tiny shadows on cushion plants huddled under it without smothering them. I have long wanted to replicate the conditions of a wild steppe with the open spacing between clump grasses, wondering if it created a special environment for some of the more elusive steppe plants, especially rot-prone geophytes. 

Festuca glauca 'Beyond Blue'  is indeed more blue that other blue urchin things widely on the market. I don't know that we really need yet another, bluer blue, brighter light, louder speaker, faster car, bigger house, taller skyscraper, oranger orange, longer johnson or whatever to make life better- the wizards are always at work. Whatever. It does of course compliment orange Kniphofia (probably 'Papaya Creamsicle' or yet another over-the-top ridiculous name for a decent plant as seems tradition.) 

Oooooo, oh lordy. The first season for Festica arizonica, it develops a very fine, very clean limey-green tussock of leaves that makes the common Mexican Feathergrass (Nasella tenuissima)  seem like an unrefined mutt. For a month or more, everyone asked what it was, in a garden of hundreds of plants. Then the flowers come out, looking a little wilder and natural and less formal, sending the plant dancing into the garden's background with arms waving comfortably in light breezes.

But then, year 2 or 3, the ratio of dead to living leaves slides down that slippery slope... But you love it and you remember its glory days, so you keep it 
just in case it's still alive.

I assumed it was fully winter dormant here, but in the third spring when fescues are supposed to turn green, this, the specimen that originally hooked my heart to them, did not wake up.  I tried burning a few to see if that would stimulate something. 
No. Dead is dead.
They've all eventually done this. Damn.

Luckily, there is one more reliable species to discuss in this otherwise mostly disappointing poop show. 

But it's big. 3' (1m) or more wide. Festuca mairei is the Atlas Fescue. Basically a green and improved version of blue oat grass (Helictotrichon sempervirens) It lives forever, it's evergreen, it tolerates dryness, and tolerates shade better than any other grass I've grown in Colorado. It is a graceful thing that my photo doesn't betray, and gets more graceful with age. It is a structural backbone plant that holds the garden together like the bass and cellos in an orchestra, never standing out with the bright melody. Being evergreen, there is no room for weeds or little flowers under it, only things like tall lilies or foxtail lilies. Why it is rare in commerce is beyond me.

Now, I have grow F. idahoensis and a few others like it in the past and I need to try them again and pay attention to their longevity. I'll let you know what happens. 

Until then, seek out the Atlas Fescue if you need a shrub-like grass, and let's cross our fingers that 'Eiler's Beauty'  keeps jammin' on:

Saturday, May 30, 2020

A new Crevice Garden in Vail

Many gardeners are deeply familiar with the small yet rich, dramatic, and beautiful Betty Ford Alpine Garden just off of I-70 in Vail, CO.

It was the first place I saw a crevice garden- a small, low feature, but it still stuck with me.

The stinging  Caiophora coronata in their alpine house.

Now, working for their curator Nick Courtens, I got to collaborate in putting in a new Caucasus Mts themed Crevice Garden.

We used around 15 to 17 tons of surface sandstone harvested from far southeast Colorado.  We also used a silty soil mix with a little compost and a a lot of chipped gravel to help lock it into the deep crevices we created. The largest stones weighed a bit over a ton, and these were brought in by small front-end loader and mini excavator. A one-ton sandstone boulder is much larger than a granite one.

I tried to challenge myself in a few ways with this- to use forced perspective to make the garden appear even deeper and longer than it is by placing the largest stones closer to the main path.  We also integrated steps for a bit of a goat path that connects visitors to a small forested path up slope in back and the nearby Japanese-style contemplation garden with its iconic "floating rock."  I loved the "goat paths" in czech rock gardens which allow the able-footed to embed themselves within the garden.

 (Socially-distanced!) Group photo courtesy of Nick
Our very mixed crew was wonderful, including Domenique from Colorado Springs, who provides the garden with its recent excellent sturdy concrete troughs (I have two Dom troughs myself) . His german background infuses him with a genuine european rock garden culture and we loved having his volunteer help.

In a similar effort to the Christchurch, NZ, design, here were were trying to incorporate a new exhibit into and existing garden, and so I used some similar strategies. We left large pockets of open soil between mounds to blur the line between crevice and open soil. We also created forms which look like giant boulders themselves so that there could be stand-alone mounds nearby and across paths that relate.  These softly rectangular shapes were inspired by the eroded rock itself, trying to suppress what might otherwise be the over-strong linear pattern of vertical crevice design in the context.

We built a wide variety of crevice sizes, from paper-thin ones formed by the mere texture of the rock, to 6" (15cm) wide slots.  Some are two feet deep. I expect for such deep crevices filled with a true silty soil, there will be wild settling next winter.

Of course, you can't put in a garden without hitting your main irrigation line and having to repair it.
And there must be at least one inconvenient rain.

"The Silk Road" Garden

The Betty Ford already has a handful of Floristically regional gardens- South Africa, Silk Road, and Himalayan, for example.  The Caucasus are not the most fashionable places where seed is hunted and flowers are celebrated right now, but they have been in the past. The Caucasus is the epicenter of the richest diversity in the bellflower family.
I myself even brought back Campanula petrophila seed from my time there exactly ten years ago.  I identified it using a volume of an old Israeli-translated "The Flora of the USSR" in the Denver Botanic's library.

Collin pays homage to the Czechs!
I expect Nick's newly implemented cold frames will provide the bulk of plants over the years for this garden.

Until then, treat yourself and visit to the ever-changing Betty Ford Alpine Garden.

Thursday, April 16, 2020

A Short Dogma of Growing Paintbrush

Castilleja miniata in the Aspen. (Populus tremuloides)

I named my late landscape company after Castilleja: Paintbrush Gardens LLC. Now that name refers to my micronursery that supplies my garden designs and also expresses my demented whims in personal plant tastes. 

Here is the way I grow paintbrush myself. There are other ways. I’ll list a few at the end.

1. Chose a species that is native to a similar climate as your own. For example, C. applegatei and latifolia have been good for growers in Washington, Oregon, and the UK. I’ve grown many from the lower elevations of Colorado but struggle with our alpine species. 

Castilleja sessiliflora is so boring it blends right in while in full bloom. Pollinators still find it. It’s one of the easiest to grow and some forms are pink and/or white. 

2. Collect your own seed. For whatever reason, I find my own seed from the last year or two or three germinates better than anything I buy. Usually. Commercial seed is perhaps old or stored poorly. An exception has been the superb seed from Western Native Seed here in CO. 

3. Screen that seed. A decent set of screens makes this really fast, or you can do creative things with folded paper (winnowing) or scraping with a credit card (reenacting Pulp Fiction). 

4. Store seeds in Fridge until you are ready to sow.

5. Sow out in fall, say October. Just two months of cold strat may not be enough. Three is more reliable.  Do it like traditional rock garden plants- low fertility and high porosity soil mix, a fine (not too deep) gravel grit topressing. Use a small 2”-4” pot. (5-10cm)

6. Pull into greenhouse in Jan/Feb. This gets the seedlings going to be big enough to plant this spring, rather than next fall. Bright light and good air movement. Look out for slugs.  Fertilize but gently. I grew half a dozen paintbrush species before I had my little greenhouse, so don’t let this step exclude you.

7. Prick out from one another, pair up with host. Letting the roots touch one another so the Castilleja finds the host easily, putting this unhappy couple in their own pot in March/April. I like to use one year old seedlings of subshrubs or other tough, long-lived and deep-rooted plants so they make a sturdy host. Eriogonum have been shown to be one of, if not the best. Use something easy that likes you.  If I have enough seedlings, I’ll often put two tiny 1/2”(1cm) plants of paintbrush per host for better odds at having one take. Also obviously pair up with a host that likes similar conditions to the species of Castilleja you are growing. I personally only bother to differentiate between mountain species and desert species.  

There was a great study done by Love and McCammon in Idaho, published in Native Plants Magazine, which had at least two big takeaways: Use eriogonums and germinate the hosts and paintbrush separately.  One friend of mine feels that seedlings may parasitize one another. 

Recently I put tiny Castilleja miniata with Penstemon davidsonii, something that happens in nature. 
I remember this better because a friend, David Sellars took a candid shot of me looking at this. 

Short but rugged Eriogonum porteri makes a great adaptable host for a number of dry american Castilleja from pot to crevice garden. Nurseries have long used Artemisia frigida or Bouteloua gracilis for Castilleja integra, which is one of the easiest species.

8. Plant out, barerooted, in April/May/June when the plants are still in active growth but before summer heat (And therefore potential semi-dormancy) has set in. If the plants are pretty leafy and grown when you do plant, I suggest pruning half of their tops off to reduce stress to their roots. Water and watch closely as well as protect from chewing bugs who will take away the other half of the plant. I like to shade them for at least two weeks until they show growth.  Now, water sparingly or to match their homeland rainfall. 

9. Enjoy and boast to friends. Really, savor it. Because plenty of species are not terribly long lived or just don’t persist in gardens.  Many species are only permanent in fairly exact conditions in nature, or in disturbed soil which inevitably settle and mature, excluding those pioneer plants.  Castilleja from dry places often go summer dormant, so don’t freak out if they turn brown in summer. That dryness and sleep might be what keeps them safe from rotting. 

Castilleja flava lived for three, bloomed for two. Maybe I let it get too dry?

Alternately, you can grow them alone until they are sturdy little lone seedlings and you pair them with a host when you plant them in ground in April. I also like to plant them next to multiple plants to give them diverse backup. Seems to help. 

C. integra with Echinocereus triglochidiatus. Seems the cactus is not happy about this. 

Also alternately, if you do not have a greenhouse or cold frame, you can do your pricking and pairing just a few months later where they grow outdoors, and plant them either the next fall or spring. I think they don’t like life in a pot so that’s why I shoot to get them planted as soon as possible.

I almost hoed this poor volunteer paintbrush. Don’t worry, an earwig ate it a few days later. 

Direct sowing. This works if that seed is absolutely ideally suited to your site.  I cannot underscore enough the danger that slugs and chewing bugs pose on paintbrush- they must be as uniquely tasty as they are uniquely beautiful. One night and one slug can take out my entire year’s crop of seedlings if I’m not religiously vigilant. Troughs or crevice gardens seem particularly helpful in accommodating species from dry climates and mineral soils. 

Some folks have used GA3- gibberelic acid- to bypass cold stratification. I’ve never been good with acid. Some folks use the fridge, but you must watch them carefully in there.  Paul Cumbleton in the UK wrote a great article for The Plantsman about growing them without a host, by taking good care of the plants from the early stages, forcing them to make their own food, and having them live and bloom this way. 

Nothing like a big, wild, unapologetic Rimrock Paintbrush. Castilleja scabrida. 

As hemiparasites, they all seem to have half the root system a plant should have, so they are just more delicate against any kind of stress you give them. In the end, they are elusive for a reason- wonderful and wild. And in wildness is the preservation of the world, right?

(Castilleja integra reseeds around the APEX crevice garden, photo by Tom Freeth)

Thursday, April 9, 2020

A Crevice Garden in Christchurch, NZ

The largest city on New Zealand’s South Island wraps around a historical and expansive botanic gardens and park, which itself is outlined by the Avon river like the bezel for a jewel.

There is a new curator, Grant, (above) for the rock garden, and the local alpine plant club, NZAGS is eager to aid him in the complex nuances of Rock Gardens. In turn, Grant has an amazing breadth and depth of horticultural knowledge and experience to infuse into his work and the alpine club. The visionary director of the Christchurch Botanic, Wolfgang Bopp (previously of Hiller Garden in the UK) encourages this connection and exchange between serious hobbyist clubs (which are repositories of expertise) and public gardens; a wise move that many botanics don’t make. I liked the guy instantly because he wore a tiny vase as a jacket pin with fresh flowers in it. 

Anyhow, the finest way to solidify a working relationship between club and botanic was with work: to collaborate on a new exhibit  (see link for video, etc) and renovation in the rock garden- which is where I was fortunate enough to play my role as designer/builder for a crevice garden in the Christchurch Botanic. Crevice gardens are relatively few and new in New Zealand, only in the back garden of alpine gardeners like Michael in Lake Tekapo- but not in public gardens yet. 

We took some time determining how to add a bold new feature without it looking out of place, (“Like a pimple” as Wolfgang said- I like that) and honoring the existing design of the rock garden at large. We wound up siting it partway into the middle of a recently renovated heath and heather collection (Erica/Calluna) but with a few “island” beds across a path, and plan for a few to actually bisect the main path and appear within the alpine garden itself across the main path.

A collection of slivered stones has always looked horrible next to massive boulders to me, so this was just the second time ever (this being crevice garden #41 for me) I’d dealt with that- the solution being to create masses and shapes with the small stones that echo the size and character of nearby large stones. Luckily, the new and old stones are also similar in color.  

The alpine plant club, NZAGS blew me away. They were as serious as any Scottish or British club but more diverse in their plant interests, and were my introduction to the indescribable hospitality, humour, level-headedness, craftiness, and hard-working dedication of New Zealanders. I got to know all of them individually on a plant-chasing field trip, so I felt like I had friends in them by the time we worked together on the rock garden. 

What I was not prepared for was that the club would take what they learned from my lecture so quickly and bravely start setting rocks- diving fearlessly headlong into learning a skill that I have admittedly failed to be able to teach people time and time again. But they learned it. Oh yes. It was my job to ensure the garden design was cohesive and that is was structurally sound as well as practical to grow plants in, so I could hardly keep up with them in not only answering their questions while they all fast-tracked their new skill, but also to guiding the character of the garden to maintain a motif that made it look whole and unified. 

Suzanne, above, did some awesome work in and out of the garden- I realized late-game that she's already  written a blog on the project that is better than mine!  Check it out here. I reckon she will build her own and I won't be surprised if she does some innovation no one has done before. 

I have a lot of experience imagining 3-D objects and spaces in the garden setting; I can envision a crevice garden, finished, in my mind, before a project starts. I must- it is my job. But when we swept the sand and dust off of the stones, and washed it off, I was startled by the beauty of what I saw.  Truly, the quality of the detail of the rock work across the installation- thanks to each volunteer- was far better than if I had been left to do it alone and even spent weeks on it.  I was so humbled by watching in real-time: my passing of a baton of my tricks and experiences to not one person, but a group, and watching them sprint off with finesse ahead of me. I had never experienced that kind of synergy even with people I’d paid as staff for years when I had a landscaping business. It was exhausting and it was amazing. I left with my head spinning and my heart exploding. 

Special thanks go to Joe and Ann Cartman, who were the perfect people to answer all the obscure things I wanted to know about the ecology, plants, animals, and people of NZ, and who also took me to see a wonderful case study of the complexity of disturbed ecologies and the resilience of natives. 

Hamish Brown is the current prez of the club who instils a supercharged combo of smoothness and energy into all happenings. He and I were not above hijacking the golf carts at the botanic. I am indebted to him for helping me during my hurried exit from the country to return home due to the virus. His family and growing style deserve an article on their own. 

A bit on crevice gardening in New Zealand: Sand, rock, and climate.
For americans, it’s best to imagine a coastal California or Washington climate- Eucalyptus and pines thrive. Dryness happens more in summer, but proximity to the ocean means dry is never so extreme as the world’s big continents. There is also a mildness of winters and summers that is not unlike the UK.  Of course, the north island is even milder; (reminded me of the Carolinas) and the interior can be drier than the coasts.  Their Mountains- not small things- create some Mediterranean-dry places and valleys almost as cold as Western Colorado- where my familiar landscapes of vineyards and orchards appear.  And of course- the mountains are shouldered with a real montane weather, and peaked with true alpine. 

Local Alpine gardeners have found that good old sand is an ideal growing medium for troughs, raised beds, and mounds, providing enough mineral nutrition without gravel fines, and not fatally drying out in summer. So this is what we used in the crevice garden on top of an old loam. 

The historic Hallswell Quarry, source of our glorious rock.

While sedimentary rock exists around New Zealand, and even a few outcrops of limestone, the place is mostly dominated by volcanic and metamorphic rocks clothed in acidic soil.  The Crevice garden was privileged enough to use the much coveted Halswel stone, which was used historically all over town, but is no longer quarried- the botanic had special permission to gather new stone from the quarry on account of being used to renovate something historical (the rock garden) and that both are council holdings. (The city government manages both the botanic and the quarry as open spaces/parks.)  Someone said our stone is an andesite; it really did feel and sound like a rhyolite I have used in Colorado. It slivers in irregular wedges characteristic of things like related basalt, which is what the large boulders in the rock garden are.  We used most of the 13 tons (12 metric tonnes) that was gathered for it.  

Gotta love that incredible leopard print rind. 

I can't wait to come back in a year or two and see what they plant, how things grow, and what they discover a crevice garden offers to gardening in New Zealand.

Time for a cuppa tea.