The Golden State: Where & How to Live, Secure, Visit, Enjoy and Thrive in California
American Rock Gardens
The third cause is too dry a soil through the long summers. This is a condition much to be faced in rock gardens in our southern states, though dry summers hit everywhere. Cacti and Sedums can always be rushed in to save the day, but proper construction of the rock garden is the secret of the pleasing of deep-rooting alpines. Faulty construction is the cause of dryness.
Many plants require fullest sun; others grow best in partial shade. Unless a rock plant is well understood in its local needs, it is advisable to plant your supply in two or three different parts of the rock garden and see which situation seems to suit better. *Sedum acre will soon die out if the soil is a bit wet or sunless, while *Sedum ternatum insists on a spot quite damp and shaded. Make your own notes from experiment and use best judgment, yet be certain that you will not always guess rightly.
Not a few, but many, of our rock plants are biennial, or monocarpic, meaning that no matter how robust the herb, when it has bloomed it sets seed and must then die. Many Saxifrages and Primulas are doomed to die after blooming— there is no way to save them except through seed. Alpine Poppy, Meconopsis, Campanula, Sedum, Sempervivum, Androsace, etc.,—all have short-lived species which must die after blooming, acting like annuals, though the rosette of foliage may live several years before bloom and death. To many a beautiful alpine I say, "You are beautiful, but monocarpic." No list of the monocarpic species has ever been made.
More than in any other kind of gardening, it must never be forgotten that those plants which thrive only in acid or alkaline soil conditions (see suggestive lists G, H, in Chapter VI) cannot by any method, except combination of chemical feeding and playfulness on the part of nature, be made to grow in the unfavorable soil. Alpine Dianthus must have good drainage and plenty of lime, while the little hardy Orchids must have a wet acid soil. To grow the two in the same pocket is beyond the power of any miracle worker, yet the enthusiast will try cheerfully at such feats.
Some alpines, long-lived in their own home, dyspeptic and over-stimulated by rich food and low altitudes, give a life-time of bloom in a season or two and expire. This is a frequent eventuality. It happens right along with Dianthus, Draba, and Viola, and related kinds of Pink, Mustard, and other families. Keep them starved and as dry as possible, and hope for the best.
