Anthyllis montana ‘Rubra’; B Leontopodium alpinum (Edelweiss); C Salvia ‘Sensation Rose’; D, E Saxifraga crustata; F Eriogonum ovalifolium (syn. Paronychia ovalifolium, Amaracea supalifolium); G Opuntia fragilis; H Thalictrum kiusianum; I Scutellaria prostrata; J Edraianthus serpyllifolia; K Dianthus x ‘Brigadier’.

 

Japanese rock gardens are dry landscapes, what we call Zen gardens. The Chinese practice a similar form called Penjing—related to bonsai—in which a large stone is “planted” on a tray or in a garden, to stand in for a jagged mountain, and artfully decorated with plants. Americans may have a fuzzier notion of what constitutes a rock garden as being any garden with rocks strewn around, what the British call a rockery. (To make rocks look natural, I sometimes bury two-thirds or more underground.) A true rock or alpine garden requires considerable thought and attention.

The plants selected from nature are those that grow in tight spaces, at high elevations, next to and among rocks. These species are usually dwarfed by evolution to help them survive in poor soil, high wind, and drastic temperature extremes. They are protected in winter by insulating snow cover. They include some of the herbaceous plants and scruffy sub-shrubs that grow above the tree line—hence “alpines.”

Consider the conditions these plants are exposed to in the thin air above the timberline. Summer temperatures are low, but in the dry air above the clouds and pollution, the sun is barely filtered. Leaves are tiny to conserve moisture; plants grow very close to the ground. Water is often tied up in snow or frozen earth. More of the plants are below ground than above, with taproots plunging deep into the earth in search of available moisture and food. In this arid climate, it can take years for fallen leaves and dead plants to decompose, leaving the soil without nutrients or layers of humus.

Summers are short and winters long. Most flowering occurs in the late spring, and all at once so the alpine “meadows” are ablaze in color. “Spring,” however, might occur in August.

All of that hard work results in jewellike plants and spectacular flowers to attract pollinators while they can. Some alpine plants and those from similar if less extreme environments may be encouraged to survive in milder climates. Heat is the enemy. The essential requirement is superior drainage—50 percent soil, 50 percent coarse sand or grit. A guaranteed snow cover in winter can’t hurt.

More genera with dwarf species include Androsace, Antennaria, Aquilegia, Arabis, Arenaria, Campanula, Delosperma, Draba, Gentiana, Geranium, Hebe, Helianthemum, Lewisia, Penstemon, Phlox, Potentilla, Sempervivum, Thymus, Veronica, and Viola.

Dark pink Armeria maratima and tiny sedums on a stone wall.