DryStoneGarden

Last weekend I went to see the Drew School vertical garden by Patrick Blanc, the French botanist who started the current green wall craze. He designed a wall in San Francisco that was installed this past February (San Francisco Magazine did a feature with photos of when it was first installed and a planting plan). I was a little skeptical of the whole green wall thing, but then looking up at his wall — four stories high of California natives with over 100 species — my doubts evaporated. The whole thing absolutely overflows with enthusiasm for plants. Two big walls covered in natives, what’s not to love.

A pair of gardeners were doing maintenance while I was there. At first I was a little bummed to see this big orange cherry picker in front of the wall, but then I realized that it was a great opportunity to find out about the wall. I mean, I see this thing and I wonder how much does it cost, how will it age, how much maintenance does it need, and who will give me one for Christmas? Watching them work, I was impressed at how easy the maintenance actually seemed. Like any other gardeners, they cut the plants back with Felcos and let the green waste fall to the sidewalk and they barely even had to bend over to work. Progress was steady. It looked quite pleasant.

The plants are essentially growing hydroponically. There’s a thin planting medium for the roots, and water mixed with nutrients drips down the wall, collects at the bottom and then recirculates. This is the first time anyone has ever tried something like this with California natives (he usually uses tropical plants), so the project was considered something of an experiment. Some species like Oxalis oregana or Mimulus cardinalis seem like reasonable candidates for a hydroponic wall, but some of the others like Artemisia tridentata and the Fremontodendron were a shock to me. It’s hard to tell from the photos, but up at the top there’s a Ribes sanguineum, a couple of bushy Mallows, and at least one Ceanothus.

The gardeners said they had done some replanting in September, but this was the first full maintenance pruning. They were cutting things back to do a one-year assessment of the planting and see how everything was growing. After a year of growth, some plants were starting to cover others. The Beach Strawberry was running all over the place, the Dudleyas were getting covered by other plants the same as they did in the Academy of Sciences green roof, the Lupines were short-lived, Penstemon heterophyllus looked like it was also going to be short-lived, but overall the plants were doing really well. The shrubs up top were growing exuberantly, maybe a little too exuberantly; the shade groundcovers down towards the bottom had the best year-round appearance. I found that in the places where the fabric showed between the plants, it didn’t bother me or diminish the effect.

Pretty healthy for a bunch of plants on the side of a building.

I definitely want to make it back in the spring when a lot of the plants have grown back in and are blooming. It really does have tremendous impact when you see it on the street.

Here’s another view of the woodland strawberry planting I showed on bloom day. The strawberries have been rather mealy this year. Two years ago they were good, last year they were okay, but this year they aren’t much good at all. I’m guessing that might be because of all these April and May rains. Also, the leaves are looking somewhat chlorotic up close, so they might need to be thinned out to refresh them. We originally put these in as a cheap, low-water groundcover, but after a big harvest of berries the second year we started to think of them as an edible deserving of more attention and respect. If anyone has a suggestion for getting fruit production back up, please let me know.

This planting started with three 2″ stubbies and had full coverage within two years. Normally, I’d be afraid of a groundcover that can spread this fast, but it’s pretty easy to control because it does all its running above ground. California Native Plants for the Garden uses a photo of it to illustrate the potential ‘weediness’ of some natives, but personally I like the look of the strawberry with the irises and alliums rising out of it. Any drought-tolerant, evergreen, native groundcover that produces berries is okay with me.

Allium, Fragaria, and Iris

Sidalcea bloom, Sisyrinchium and Fragaria foliage, in February

The sidalceas disappeared into the strawberry patch a couple of years ago, with only their flowers showing unless you hunt for the leaves. I like its ‘What plant are those flowers coming from?’ effect.

Blue Eyed Grass, Sisyrinchium bellum, last month

Mostly Fragaria vesca

We put in a single Beach Strawberry, too, which is now the dominant plant in its own corner of the planting. It has sent out runners through the rest of the planting that send leaves up for a bit of textual contrast. Before growing the two strawberries, I used to get them confused, but side by side it’s not hard to tell the difference. The beach strawberry has a harder, darker, thicker, glossier leaf. Flowers are bigger and often set deeper within the foliage. I’ve never seen a berry on it. Woodland strawberry unsurprisingly prefers part shade, while beach strawberry is happiest, again unsurprisingly, in coastal full sun, but both plants have worked in pretty much every situation we’ve tried them.

Fragaria chiloensis and Fragaria vesca

Fragaria chiloensis, on the left, Fragaria vesca, on the right

Quercus garryana or lobata

This is one of the best oak trees I’ve seen, in a Lafayette yard where we did some work a couple of years ago. I was back to check on the pondless waterfall this past week (still no leaks or pump problems, knock on wood), and I was glad to see the oak is just as amazing as I remember. At the time I thought it was a Garry Oak, but apparently the various arborists and oak experts who have looked at it have given several different ID’s, saying it could be a Garry Oak, a Valley Oak, or a hybrid between the two. They also differ on their estimates of its age. Everyone agrees, though, that it’s big and old and beautiful.

Wow

To my complete astonishment, the highlight of my day yesterday was the Lowes parking lot in Concord. It has the biggest, bloomingest, most successful wildflower meadow I’ve ever seen. I have some cynical thoughts about it — it was probably done to appease environmentalists or the planning commission, it was probably amended with all the damaged bags of Miracle Grow, Monsanto probably supplied the seed mix — but it was impressive nevertheless. Not something I expected to see at a big box store.

Tidy Tips, Layia platyglossa

Tidy Tips predominated in the bio-swale, Chinese Houses on the berms.

I had never been to Lowes before and it turned out to be even more like Home Depot than I expected, but my hat’s off to whoever is responsible for that meadow. It’s pretty incredible.

Tidy Tips, Baby Blue Eyes, Alyssum, and African Daisy

Elephant Tree at Dusk

Here are some more plant photos I took in Baja in the desert around San Ignacio and Cerro Colorado, along the coast near Bahia Concepcion, and further south near Cabo Pulmo. My first go at taking photos in low desert, pretty fun, as my favorite things in the plant world are multitrunked trees with interesting form and bark, and Baja is pretty much an entire landscape of beautiful multitrunked specimens with interesting form and bark. Elephant trees were my favorites, but there were other stunning ones: Palo Verdes, Palo Blancos, Cardon Cactus, Organ Pipe Cactus, Adam’s Tree known in Spanish as Palo Adan (Fouquieria diguetii, the southern form of Ocotillo) and Limberbush (Jatropha cuneata), which I’d never heard of but really liked. So many good ones. I suppose some of them are technically standards or semi-standards, but practically all of the plants down there grow with the interesting form I associate with multitrunk trees.

Limberbush, Jatropha cuneata

Cardon

The Cardones come in graceful or stubby forms.

Cardon Multitrunk

Organ Pipe Cactus

Elephant Tree

Burseras

We saw hillsides that had an amazing specimen every twenty or thirty feet.

Bursera microphylla, Elephant Tree aka Torote

Torote means ‘twisted.’

Elephant Tree Trunk

Graveside Fouquieria diguetii, Palo Adan

Zero Leaves, One Bloom Cluster

Lots of Leaves, No Flowers

In the drier sections most of the Fouquierias were leafless, with maybe a few token blooms to keep the hummingbirds and visiting gardenbloggers happy; down south a lot of them were in full leaf with fewer flowers. Does anyone know why they’re called Palo Adan or Adam’s tree?

Fouquieria diguetii at Playa Requeson

I remember something incredibly spiny was keeping me from backing up any more for this photo.

Palo verde, aka Desert Willow

I’m partial to the name palo verde, but desert willow, another of its common names, seems appropriate too. Leafless they looked a lot like Japanese maples, but in full leaf they were indeed willowy.

Green Sticks

Roadside Palo Verde

As far as I’m concerned, they’re pretty even when they grow along the highway with trash scattered around.

Mesquite Tree

We started calling the Mesquites ‘Palo Gris’, because their trunks are gray but their green twigs and foliage resembles a Palo Verde. They’re actually a pretty sweet little tree, I think, just not as showy as the Palo Verdes and Palo Blancos. I read somewhere that some miners in Baja once found a root 50 meters deep.

Palo Blanco

Palo Blanco is a perfect common name, but if Palo Verde gets desert willow for a second common name, I think Palo Blanco should also get a second name and be called desert birch. They did seem biggest and happiest at the bottoms of washes and arroyos where they could find some extra water.

Palo Blanco

Palo Blanco

Cerro Colorado in the distance with Volcan las Tres Virgenes beyond it

I mentioned that we started bicycling from San Ignacio, an oasis town about half way down the Baja peninsula. Before we started riding, we spent a few days exploring the desert and checking out the plants there, and especially checking out the succulents on Cerro Colorado, a volcanic hill a few kilometers from town.

Closer to the hill

If you’re interested in succulents, Cerro Colorado is the place. The Center for Sonoran Desert Studies/Desert Museum did a survey and found 44 unique species, which they claim is the highest number of succulent species of any spot in the southwestern U.S. Would that then make it the highest number of any spot in the world? I don’t know, but there’s a ton of succulents there, regardless. Anita and I did our own personal survey and identified 19, which we’ll obviously have to improve before we can start leading botanical bicycle tours of Baja (now accepting reservations for winter 2031). Looking at the species list for the hill, I see that it broadly defines a succulent as just about any plant that has tissue designed for storing water. The list includes a couple of Asclepias species and a bunch of caudiciform shrubs and vines: cucumber relatives, shrubby euphorbias, a wild fig, and two species of elephant trees (Bursera). Some of those are plants I wouldn’t have considered succulents, but then I’m not a botanist, and with 24 species of cactus, it’s not exactly lacking in conventional succo’s.

Organ Pipe and Cardon

Cardones

More Cardones

Barrel Cactus

I think these are two different species of barrel cactus. I lost track of all the chollas. We could tell there were several different types, but the desert museum lists eight, including hybrids. A couple were jumpers.

Cholla and Barrel Cactus

Slipper Plant, Pedilanthus macrocarpus

Fouquieria Trunk with Cardon Trunk

Fouquieria Trunk with Organ Pipe

Agave cerulata subcerulata

It’s probably the spiniest place I’ve ever been, but plants are spaced far enough apart that we could make our way through it as long as we occasionally pulled spiny branches out of our way. I found that walking with all those spines everywhere kept my attention always focused on my immediate area and each plant immediately in front of me, so that I was constantly looking up to discover yet another awesome specimen in front of me, over and over and over.

Elephant Tree, Bursera microphylla

Elephant trees get the nod as my favorite plant down there. Has anyone seen or grown one in the Bay Area?

Red Elephant Tree, Bursera hindsiana

This is probably the best trunk I saw on a Red Elephant Tree while I was down there.

Limberbush, Jatropha cuneata, in the Euphorbia family

There were two kinds of Jatropha. The other one, J. cinerea, looks a lot like the mexican redbud, but with somewhat swollen-looking branches and twigs.

Palo Verde

The hill had great palo verdes. They aren’t a succulent, but they have chlorophyl and photosynthesize on their wood, which seems like justification for getting in with the succulent photos.

Palo Verde

Cerro Colorado from the bridge near San Ignacio