Plants, Stone, California Landscapes


Archive for April, 2009

Mallorcan Dry Stone Walls

mallorcan style wall

mallorcan style wall

Posting about the angled stone wall in this year’s garden show seems like a good excuse to post about the Mallorcan style wall we did with Mariposa Gardening and Design in the show last year. It’s not as eye-catching as the angled stone, but the building style is unique in its own way. Personally, I didn’t lay a single stone on the wall–I was a bit skeptical about building a wall and then taking it apart five days later, part of the reason I like stone is that it is the longest-lasting building material on earth, so instead my contribution to the garden was flagstone steps that I could afterwards re-install in a real garden–but it was a nice wall and it deserves to have some internet presence.  A lot of the stuff in the garden show is just facade work, but the crew built a real wall, thirteen tons worth, pretty cool and pretty crazy.

Mallorcan walls are also sometimes called polygonal walls because they use five-sided stones laid in an arch pattern; traditional walls use four-sided rectangular stones laid in linear courses. One of the sacred rules of traditional walls is to break every joint, but with a polygonal wall the joints zigzag enough that the rule doesn’t apply. Instead, the rule for a polygonal wall is to have every stone touched by five others. Instead of trying to create a flat surface for the next stone, you try to make a cradle for it, and instead of vertical and horizontal lines, you create arches. The idea is that the adjoining stones form an arch around any given stone, so if that stone falls out the other stones will still hold together and the wall won’t fail. In theory, if you pick a stone, you can see a little arch of other stones around it.

mallorcan wall arch detail

mallorcan wall arch detail

The walling style is really effective at making tall, strong, long-lasting walls out of irregular stone. Mallorca is full of walls hundreds of years old, and examples I’ve seen on the internet are often ten or twenty feet tall. To work on the walls, workers pound metal bars between the stones and then put boards across the bars to act as scaffolding. A lot of the walls are pretty rough looking but at the same time really appealing because of their size and strength. The walls get capped with European-style vertical coping stones, which adds a nice touch of style and self-consciousness to the rather rough, naturalistic stonework. Our wall in the garden show was made with Napa basalt, the closest Bay Area equivalent to the limestone they have in Mallorca.

The Stone Foundation has a beautiful Mallorcan wall in their write-up for the 2007 workshop and another in their write-up for the upcoming 2009 one. DryStoneWalling has photos of two walls, one that’s retaining and one that’s freestanding. Below, I put one of my sets of flagstone steps with a section of Mallorcan cheek wall.


Allium Unifolium

Allium unifolium

Allium unifolium

We’ve been starting to add California native bulbs to our home garden and our landscape plantings, and so far, Allium unifolium is one of our favorites. A lot of the native alliums require perfect drainage and a summer dry period and would be difficult to source even if you thought you could get the growing conditions right. A. unifolium, though, is easy to find and grow; we read that it’s supposedly the most clay tolerant of the alliums, and so far that’s been the case. Also, because it’s considered garden worthy (the Dutch like it) and not just for native purists, you can actually find it in sufficient quantities to make an impact in a large garden, where it will spread somewhat aggressively if it’s happy. It’s beginning to bloom in several of our gardens now.

Allium unifolium

Allium unifolium in our garden

We were recently at the Regional Parks Botanic Garden at Tilden for their native plant sale, and I took pictures of the alliums that were blooming. The bed’s aesthetic (three foot high bed of stone holding 4-12 inch high plants) is more for collectors than for casual visitors, but it has some interesting stuff, of which Allium crispum sounds like the best bet to try in a garden. The Pacific Bulb Society has a good info page for North American alliums. Far West Bulb Farm also has photos and info and might be a source for some of them. I put photos of four alliums and the raised bed below. (more…)

Vegi Garden Flowers

variegated iris

variegated iris

We’ve been collecting photos of the winter vegi garden for a class that Anita will be teaching in the fall at Heather Farms, and this is our latest and possibly last crop of photos. We’re letting some things–the mache, the meadowfoam, the miner’s lettuce–go to seed, and a few things are entering or yet to reach their harvest phase–the favas and alpine strawberries, and later the onions and garlic–but most of the garden is now heading towards the summer phase, so this might be the last of the photos. One of the ideas of the class will be that folks should try to have a lot of flowers, including natives and perennials, mixed in with the edibles to attract beneficials. I put rest of today’s photo harvest below.

Golden Mummies

golden mummies & aphids

golden mummies & aphids

Please excuse the rather unpleasant photo. Aphids are gross, but golden mummies are one of the best things I ever learned about IPM.

We’ve had a couple of outbreaks of aphids this spring, first with the lupine when it put out a big flush of new growth and now on our kales as they begin to bolt. Golden mummies are the brownish, mummified carcasses of parasitized aphids; wasps lay their eggs in the aphids and the larva eat the aphids from the inside, leaving the dried husks. If you aren’t familiar with them, click on the photo and you should be able to see the difference. In the garden, another way to tell the difference is that aphids move and mummies don’t.

When you see an outbreak of aphids, the presence of golden mummies is one sign that natural predators are present. Count the aphids and golden mummies on a leaf, and, if the outbreak includes at least 10 percent golden mummies, the natural predators will deal with the outbreak for you. Spraying would kill the natural predators along with the aphids and therefore be counterproductive, though aiming a spray of water against the aphids to knock them off (which actually kills a large percentage of them, while not harming the beneficials) is okay if you want to speed the process. 

In the photo, I count 14 golden mummies (mostly on the right, but three in the population of aphids on the left) and estimate about 100 aphids, so our IPM is working. Our earlier outbreak on the lupine was the same way, and it resolved itself without intervention.

ryan 4/22

Wisteria Showers

the wisteria shower

the wisteria shower

I swear this is the first time I’ve ever posted a photo of a man taking a shower on the internet.

This is our wisteria shower. Most of the year it’s a bamboo shower, but in April you get to shower with the wisteria blooms cascading around you. The shower is on our front porch, but so far no one has walked in on either of us and the bamboos in pots around the shower do a good job of screening. Guests are usually a bit skeptical at first, but they become hooked as soon as they try it. We have an indoor shower, too, but it’s much nicer to shower outside, especially when the wisteria is in bloom.

Last year we got a much better bloom and two winters ago we had a frosty winter that had the wisteria covered in blooms. It’s an old, well-established wisteria with plenty of space to ramble so we’ve been slack about pruning it, but this year we’ll probably motivate. You prune wisteria twice a year to create spurs and it’s generally a good idea to stay on top of your vine, show it who’s boss. The Monster, in Sierra Madre, CA, is the most extreme example of what happens if you let your vine run wild. That wisteria, a single Chinese vine planted to cover a house, eventually swallowed up the house and caused it to be demolished, took over an entire acre of land, has an estimated weight of 250 tons and blossom count of 1.5 million per year, branches over 500 feet long, and is listed as one of the seven horticultural wonders of the world. The town now has an annual festival celebrating it.

Our wisteria isn’t quite at that level, but it’s one of the great features of our garden. We have two vines in our yards, a younger Chinese vine, Wisteria sinensis, and the Japanese one over the shower, Wisteria floribunda. Chinese wisteria is the more commonly planted variety around here, but the Japanese one is more fragrant and has longer flower clusters, so we’re glad it’s the one over the shower. Our landlord is the one who planted the wisteria, and he did it before he even added the porch, let alone the shower, but it turned out really well. I think one of his motivations for the shower, beyond mere aesthetics, was that the bathroom is old and somewhat poorly ventilated, and it would generally be a good idea for the house if we showered outside, but, whatever the reason, he added a great feature to the house, one we’ll probably try to recreate in any other house we might ever move to.

EwaintheGarden has a great gallery of wisteria photos.

ryan 4/19

Indian Paintbrush and The Watershed Nursery

indian paintbrush

Indian paintbrush

Indian paintbrush is one of my favorite native wildflowers to see hiking, and one of the more unusual plants in any of our gardens. It is a hemiparasite, meaning it takes nourishment from a host plant but also photosynthesizes for itself. To grow it, you have to germinate the seed and then put it in a pot with another plant and wait for them to join root systems; when I read about the process, it sounded like a huge pain in the neck. Now that it’s established, though, it’s really carefree, growing with an Artemisia californica in some of the heaviest clay soil we’ve ever planted in. The two plants have similar foliage, so you don’t notice the paintbrush for much of the year, but then the blooms pop out from under the shrub and carry on for a long time before fading back and going dormant for the winter.

We got the plant at the Watershed Nursery, the only nursery I’ve ever seen selling it, and, in our experience, the best source for natives in the area. East Bay Nursery and Berkeley Hort and Annie’s Annuals are all good for natives, too, but they mostly sell cultivars and their plants come from all over the state, not really “native” in the purest sense. The Watershed Nursery, on the other hand, sells Bay Area natives, grown here in the Bay Area from seed collected here in the Bay Area. If you want to plant the same plants that you see when you’re out hiking, it’s the nursery to go to.

The paintbrush came in a gallon pot with the artemisia, but the Watershed Nursery grows most of their stock in restoration tubes. Restoration tubes, if you’ve never used them before, have some advantages over the typical gallon pots you find in the typical retail nurseries. Compared with a gallon-sized pot, it takes less time for the plant to fill the narrow tubes with roots, so the plant will cost less while still getting its roots just as deep in the ground, and the plants haven’t spent as much time in potting soil, so they are quicker to adapt to whatever soil you plant them in. The tubes have vertical ribs to keep the roots from girdling, and they are open at the bottom so the roots air-prune instead of circling the bottom or heading back up to the top. You don’t have to spend as much time undoing a root ball, so you can plant a lot more quickly, and you don’t do as much damage to the roots, so the plants establish themselves almost immediately. The plants look small when you first plant them, but they often seem to explode out of the ground. I’ve recently been passing by several yards where we planted a lot of Watershed Nursery plants, and they’ve all been looking big and healthy and happy. They have a sale every year during the upcoming Bringing Back the Natives Tour.

The Kew seed slideshow has a cool photo of an Indian paintbrush seed.

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