My husband wondered what I was doing, stirring up a sludgy batch of portland cement, sand, and peat moss in a wheelbarrow. It looked peculiar, I must admit, but I was just following a recipe.
Like whipping up bearnaise sauce in my kitchen, I was concocting one version of Hypertufa, a simulated-stone concrete mix, in order to make a trough for some choice alpine plants.
Early in the century, some clever English gardener discovered that discarded watering troughs made perfect containers for his rare mountain plants. Rock gardeners in England and America began collecting old stone troughs and sinks as avidly as the depression-glass collectors of today. Soon the supply of old troughs was exhausted and imitation began.
Today hobbyists are making troughs, pots, and free-form containers from Hypertufa, using one of several formulas that add peat moss, perlite, or vermiculite to a concrete mix. H. Lincoln Foster's favorite mix, listed in his book ''Rock Gardening,'' blends one part portland cement, 11/2 parts peat moss, and 11/2 parts agricultural perlite.
These pseudo-stone mixes are preferred to concrete by rock gardeners for two reasons:
* The containers built of Hypertufa are lighter and therefore easier for gardeners to move around in their gardens.
* As the trough weathers, the Hypertufa surface looks more like stone.
The trough I built is along ordinary rectangular lines. After it was hard, cured, and had been rained on a couple times, it was ready for planting. I put small pieces of screening over the drainage holes and then filled the bottom inches of the trough with pea-size gravel, since all alpines like good drainage.
Next I added a lean soil mix and irregularly contoured the surface of the soil. An interesting rock or two can enhance this sort of miniature landscape.