The Golden State: Where & How to Live, Secure, Visit, Enjoy and Thrive in California
American Rock Gardens
Fatalities
THE most disturbing factor in caring for a rock garden is the quick and complete death of many choice plants. In no other garden are the fatalities so great. Of the many hazards in operating a rock garden, the uncertain life of the plants adds the greatest variety as well as sadness of heart. No matter how careful the construction or faithful the care, there are always the absent who will nevermore return. At times it is not possible to diagnose the immediate cause of death, but the emptiness of pockets is most visible in the spring. Often winters are not the only tests, for hot, dry summers or very wet ones bring also a long list of plants gone back to their native happy country. Cultural data is given us in books, and we gain by experience, but the happiness of each plant is largely from local factors. What I learn by sad experience in my rock garden may not come to another garden, and conditions vary with every region.
The weedy unbeautiful kinds live long and in crease. So dubious have I become of the virtue of new alpines that when I see one growing well and not yet in bloom, it gets catalogued as a weedy plant of little beauty of flower or foliage. Often it is not a case of handsome is as handsome does. It is too true that the less desired do flourish most amazingly. The most beloved Primulas are most difficult to grow.
There are many causes of the death of rock plants. Some, lauded by M. Correvon, at Geneva, or hardy in Oregon, will not survive the cold of New England, unless well covered with snow, and often not then. For every section of our country, there is a list of plants not hardy, but no one has made such lists. What is hardy one year may be fleeting the next. At Boston I begin this list of "too-tender-to-live" with Shrubby Gromwell (Lithospermum fruticosum), usually called "Heavenly Blue." By no magic can it be made to survive a New England winter. Plants of like vigor are hopeless for this climate, whatever the dealers' catalogues may say.
Abundant summer rain, unless drainage has been fully provided, will kill off alpines in quanty. Heavy growth is encouraged, and then quick decay begins in the crown of the plant Any fertilizer at all, save a'meagre diet of bonemeal, makes for too much growth. Sand- and gravel-packs about their necks, steep declivities of rock face to shed all rain, a poor soil to retard growth,—these are preventive measures against the germs of decay. Try growing some of the mossy Saxifrages without these precautions and see how quickly a rock plant can die.
Often the natural soil is wet, heavy, mostly of clay. Well, half your rock plants will die quickly and quietly in that soil, and only the tough kinds can survive. A clay soil is sure death to most rock plants. It is necessary to make over the
clay soil, and for the common rock plants, even, the sand-peat-loam mixture must be used. Go over instructions in Chapter II and see if the soil preparation was properly done.
