DryStoneGarden

Three Rivers Flagstone

One of our clients calls Three Rivers flagstone “purple zebra,” which is a pretty accurate description. It always catches our clients’ eyes when they visit the stoneyard, though they often balk at the price, as it became really expensive a few years ago and is probably the most expensive flagstone commonly available in the Bay Area. It’s from one of the largest flagstone quarries in the United States, located up in the Sawtooth Mountains in Idaho. The quarry wanted to expand and the Bush administration, in their inimitable way, told them to go right ahead and not worry about doing an environmental impact study. An environmental group, the Western Watersheds Project, which owned a wildlife preserve adjacent to the quarry, then sued, and a judge agreed with the environmentalists that yes, U.S. law does require environmental impact studies, and temporarily shut down work at the quarry. Everyone settled out of court and the price then went up a couple of hundred dollars to around $750/ton.

I’ve seen the stone described as a type of quartz-sandstone and as argillite. Answers.com defines argillite as “an intermediate between shale and slate, that does not possess true slaty cleavage,” which sounds about right, except that I would add that Three Rivers is really hard and heavy. (Can I say that I prefer my stone with a bit more cleavage? It’s true. Cleavage is the tendency of stone to break cleanly.) The swirls of color in Three Rivers come from irregular mineral layers which look cool but make the stone inclined to break irregularly. The patio in the photo, for instance, has rougher, wider joints than I would do with a cleaner-breaking stone like a sandstone. To get tight joints with Three Rivers, you pretty much have to cut everything with a saw. We usually only use Three Rivers for stepping stones, paths, and small patios; it can look too busy when used for larger areas.

Quarriesandbeyond.org has links to info about the Three Rivers quarry on their list of quarries in Idaho.

Three Rivers Flagstone Patio

tenacatita, mexico

Beach front property in Tenacatita, Mexico, south of Puerto Vallarta. I like the juxtaposition between the permanent stone foundation and the more transient tent and palapa. Tenacatita has various parties making claims on the beach front property, so no one has been willing to invest money into developing it. Some day, no doubt, a developer will line the beach with condos, but in the meantime it’s a winter home for migratory Canadians. I have a few photos of walls from the area below.

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hacienda de oro restaurant

We visited the Puerto Vallarta Botanical Garden. The garden was founded in 2004, and we were curious to see such a new botanical garden. One of the challenges of landscaping is making the planting interesting while you wait for the plants to grow, so it was interesting to see what they did with a new botanical garden. Their stated mission is to promote sustainability, protect native rainforest species and to develop the largest collection of Mexican orchids in the world. They already have a good section of native bush and an interesting shade house and conservatory, but for now, while they develop their orchid collection and wait for their revegetation plantings to fill in, the best parts of the garden are the swimming hole and the Hacienda de Oro restaurant.
I don’t mean that in a negative way; the swimming hole and the restaurant are great, and it was the most pleasant meal we ate in Mexico. The tortillas and vanilla ice cream are made there on site, our table was up on a balcony with a great view and a fresh breeze, and the service was endearingly slow and over-solicitous. We found a lot of details throughout the garden to interest us; photos are below.
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One of the gardens created during the last eight years. I drive past it just often enough to forget about it and then have it hits me again with how many crosses there are (4229 as of 1/18/09).

Wikipedia has details about the memorial.

ryan 1/19/2009

Cabernet Stone Corner

It seems like whenever clients call us about terracing a slope on their property, the slope is actually too steep to terrace with dry stone. The slope usually turns out to be steeper than 1:1, one foot of vertical for every foot of horizontal (a quick way I estimate is to stand on the slope and measure or eyeball the distance straight out from my shoulder, my shoulder is five feet high, so if the distance to the slope is five feet then the ratio would be 1:1, ten feet would be 1:2, fifteen feet would be 1:3, and so on; if the distance to my shoulder is less than five feet the slope is too steep), and that math just doesn’t lend itself well to dry stone retaining walls, which rely on their thickness and weight to hold back the weigh of the slopes they retain. For instance, a two foot high wall needs to be a foot thick at the top, so if your wall rises two feet on a 1:1 slope, it only creates two horizontal feet and one of those feet will be taken up by the wall; your net gain is only one foot of flat planting space. It’s rarely worth the money or effort, so we usually end up building a wall at the base of the slope and then planting the rest of it with plants that thrive on slopes.

This little planting in San Francisco is the first time we’ve actually terraced a slope, though, in reality, it barely qualifies as terracing; it’s more like one wall split into two shorter walls. We could have built it as a single two and half foot high wall. But because the whole planting is at eye level on top of a thick concrete retaining wall, we didn’t want to be adding another giant wall to further loom over people. So we split the wall into two separate walls and then further softened the impact of the stone by setting the lower wall back from the concrete to create space for plants.

For the plants, we chose ones that are soft textured, drought-tolerant and mostly native to coastal California. A few of them are considered rock garden plants, a somewhat subjective term, but typically rock garden plants like sandy or gravelly soil, tolerate or enjoy reflected heat from stone, have a smaller size, and are best appreciated up close and at eye level, all elements of this planting. And then a few of the plants like the Myrica and the Phormium are standard landscaping plants for San Francisco. A photo of the whole little planting and the plantlist is below. Read the rest of this entry »

We went to a planting party in the Mission this weekend. I hadn’t noticed before, but many parts of San Francisco don’t have hellstrips, the strips of dirt between the sidewalk and the street. Whole neighborhoods are wall to wall concrete with only an occasional little cutout for a street tree. It’s not good; all that concrete causes various problems, especially with stormwater management. Stormwater has nowhere to infiltrate during a storm, so it ends up in the city sewer system where it sometimes overloads the system and causes sewage to dump into the streets and the bay. Yuck. Much better to have a hellstrip, which allows the water to infiltrate instead of running straight into the sewers.

Plantsf.org is a non-profit in the city that encourages and helps people to remove concrete and create planted areas on their streets. Their website has demonstration photos and information about the process; there’s a permit to apply for and grant money is sometimes available to help pay for materials. If I live in SF and had a sidewalk seven feet wide or wider, I would go to their website immediately.

Thirty different homes were getting plantings at the project we helped with, enough to to make a big difference in the neighborhood. A lot of volunteers showed up, the weather was great, and I got a free ice-cream cone.

ryan 1/14