The Incredible Growing Rock

What is Tufa Rock?

Tufa (pronounced "toofa") is formed when water evaporates from lime-rich waters, leaving calcite (calcium carbonate) to crystallize, often with impurities of iron oxides (rust), which give tufa its yellow and red coloration. It is formed on cliffs, caves and quarry faces where limestone is naturally occurring. This rock can form very quickly if conditions are favourable. Plants, mosses and invertebrates often become encrusted in the calcite, and preserved as fossils.

"One garden writer, ninety years ago, described tufa as "the rarest and most costly garden rock". Since then, numerous rock garden books refer to tufa with various degrees of enthusiasm for its many fine gardening qualities without telling the reader where it may be obtained. In fact, the development of 'hypertufa' is generally attributed to the fact that real tufa is practically unobtainable. The fact is that hypertufa, whatever its advantages over concrete for troughs, for example, has very little resemblance to the real thing.

Peter Erskine, past President of the Alpine Garden Society (AGS) in England, commented in an article on the use of tufa in the open garden several years ago that there were only two known sources in the United Kingdom and of those, only the one in Wales produced reliably good tufa. Harry Jans, a prominent Dutch rock gardener who gave a remarkable photographic presentation of his construction of a tufa wall at the Spring 1996 North American Rock Garden Society's Western Winter Study Weekend in Victoria BC, described having to drive some 400 miles into East Germany with a truck to get his own supply of tufa.

It is widely used in Czechoslovakian rock gardening, apparently, but the fact that tufa is advertised in the AGS Bulletin for sale by mail in quantities suitable for shipping by post tells us something about both availability and cost in Europe.

And what about North America? About twenty years ago there was a supply available in Upper New York State "by appointment", but that seems to have dried up long since. Again, about twenty years ago, Seattle area gardeners were able to get some from a source about sixty miles away; and that, too, seems to have dried up. At present, we know of no U.S. source of tufa for gardeners.

As for Canada, it seems that it is an article of faith among older Canadian rock gardeners that "There is no tufa in Canada!" (This is almost always said rather dogmatically, as if there can be no argument about such an obvious fact). And that settles it. Facts, however, often collide with conventional wisdom: There is tufa in Canada, and plenty of it, too! In fact, the supply seems to be almost unlimited, and it is located in Brisco, BC on the Radium-Golden Highway near the Bugaboo Road on the Wolfenden family's farm. There is no need for the traditional secrecy about location, because the Wolfendens are developing their deposits for garden use. It can be bought at the farm or arrangements for shipping in any quantity can be made, and made at a very reasonable price, too.

The Brisco tufa was first identified by me (Rod Sykes) of Calgary in the Spring of 1993 when Winston Wolfenden, knowing that I was a rock gardener, suggested that I might like to take some of the weathered rock that made the upper areas of pasture so poor for cultivation or grazing back to Calgary with me. The rock seemed to match everything I had ever read about tufa, and so I decided to ask the experts. Two of them told me without hesitation that my rock couldn't possibly be tufa "because THERE IS NO TUFA IN CANADA".  They didn't even need to see it to know! And then, because I was so persistent in my ignorance, Sheila Paulson brought one of the experts to my garden one Sunday morning to show me where I was mistaken. It is always pleasant to see an expert at a loss for words. They, and others experienced with tufa, have since agreed that the Brisco tufa is not only genuine tufa, but also some of the best that they have ever seen.