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"An artificial rockery is usually a bit of frankly simple make believe. Nine times out of ten there is something about it half funny, half pathetic, so innocent, so childish is its absolute failure to look like real rocky ground."
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"I would have everything planted in longish drifts, and above all things it should be planted geologically; the length of the drill going with the natural stratification of the dell. In all free or half-wild garden planting good and distinct effect (though apparent and enjoyable to every beholder, even though he may not perceive why it is right and good) is seldom planned or planted except by the garden artist who understands what is technically known as "drawing." But by planting with the natural lines of stratification we have only to follow the splendid drawing of nature herself, and the picture cannot fail to come right."
-- GERTRUDE JEKYLL.
THE ROCK GARDEN
A PRETENTIOUS pile of rickety rocks propped with cobble stones, and a few sickly, sun-baked plants straggling over them in a meaningless manner -- this would seem to be the prevailing idea of a rock garden in too many American dooryards. Yet a rock garden, treated in a naturalistic and practical way, and fitted into the surrounding scene as if it really belonged there, may be the most charming feature of a place. Moreover, it may become the refuge of many unique and interesting plants that would grow nowhere else, or of others, not alpine, yet that thrive best among deep, cool, moist pockets of soil between the rocks where one almost never sees them in our over-conventional gardens.
If there are no rocks on one's grounds, nor within easy hauling distance, not only is the cost of making a rock garden a serious matter, but the artificiality of it is likely to be so apparent as to make the effort scarcely worth while. Only the Japanese seem to have the selecting and placing of garden stones reduced to an art that defies detection. Lives there the American who would make long pilgrimages to the mountains to secure one weather-worn rock of just the right shape and tint to fit into his garden picture? Where some fine rocks in a desirable situation naturally occur on one's grounds, of course it is sheer waste not to use them, and painfully inartistic to create artificial rockwork unless it can be so skilfully added to what nature offers as to seem to be a part of her design. Immense sums of money and glorious opportunities for beauty have been wasted in blasting and burying rocks on estates in Connecticut alone in order to make "gentlemen's country seats" conform with conventional methods of treatment elsewhere. Let no one deplore the possession of boulders, outcropping rocks, rocky seams, crevices, and ledges, for the trained imagination of a landscape gardener should find infinite possibilities of beautifying them at a fraction of the cost of reducing the land to a level commonplace. The opportunity to preserve the land's individuality, no true lover of nature or of gardening will neglect. One of the most beautiful estates in this country includes an abandoned stone quarry, now transformed by the subtle and sympathetic art of the gardener into the happy home of myriads of rock-loving plants. Your true gardener never spoils nature: he trains and develops her.
Since the situation of any kind of a garden should dominate the whole scheme of its development, few hard and fast rules for the making of a rock garden can be laid down. However, it is certain that the site needs to be selected with extra care, for most of the failures to grow alpines and other rock-loving plants in this country have resulted from attempting to copy the rockeries of England instead of adapting them to our drier, more sunny and more extremely hot and cold climate. But at last we have learned that rocks not screened from the sun by trees, or so situated on a northern slope that only the weaker rays of morning or afternoon sunshine slant upon them, are more likely to scorch or scald plants than to aid their growth. We may not attempt to naturalise in exposed and sunny situations around our homes those charming little cushions, rosettes, tufts and creeping plants from the cooler mountains above the timber line, where moisture-laden clouds and mists almost always envelop them. Nor will alpine plants, however carefully guarded from our mid-summer sun and drought, thrive in a situation swept by the wind.
TAKING ADVANTAGE OF OUTCROPPING ROCKS. A CARPET OF CREEPING PHLOX; ROCK-LOVING PLANTS
IN EVERY NICHE ALONG THE LEFT OF THE PATH AND FESTOONS OF WISTARIA BLOOM OVER THE BOULDERS.
Evergreen trees make the best wind-break where a rock garden cannot be planted on a protected hillside, but they must be kept at a distance where the roots of the guardians will not rob their wards. In addition to the taller evergreens, hemlocks, pines, firs, and cedars, that are useful chiefly as a sun or wind screen in the background, we have learned to utilise the broad-leaved native evergreens for closer shelter -- rhododendrons, laurel and bay, whose fine roots never forage far; and to punctuate points of greatest interest, or exposure, among the most sensitive plants, with those charming little dwarf pines, junipers, thuyas and retinisporas from Asia that nevertheless seem to belong to our rock gardens by every natural right. In the lee of a very small evergreen a choice alpine plant may be induced to live contentedly, whereas, without the shelter, it would as certainly die -- a fact mentioned in this connection only to show how almost any desirable site, however exposed, may be utilised for a rock garden with the help of proper protecting plants and trees.
Rock gardens are not necessarily made on natural slopes to simulate a bit of wild mountainous scenery in miniature, although the best of them are. Some very successful ones have been created on what was once level land. What is known as an underground rockery is made by excavating an open passage down into the soil and banking up the earth on either side of the cutting as fast as it is dug, all the top soil having been previously removed and saved to spread over the banks when finally graded, and to place in pockets between the rocks where plants are to be set in. The width of several feet at the entrance to the passage may be varied and increased to fifteen or twenty feet farther on; and the depth, gradually increasing as the cutting proceeds and then diminishing again toward the exit, will vary according to the amount of soil thrown up on the banks. After rocks have been added to the slopes, an excavation of only three feet may make a total depth of six. Of course, the cutting is not done in a straight line, but in a gently curving one, in the hope of creating an impression of naturalness as well as affording a variety of exposures to plants of varying needs. The marvel is that such an absolute fake as an underground rock garden can ever be convincing. Needless to say, it takes an artistic genius to make it so. Yet there is a rockery of this purely artificial type at Kew Gardens, London, which is a joy to all beholders; another good one, cut into a bank by the same underground method and executed by the same landscape gardener, thrives on the grounds of Smith College, Massachusetts. Many others are partly natural and more or less cut out underground; but never in this dry land of ours was a successful rock garden made on a sunny southern slope, where the rain runs rapidly away or evaporates, unless a cascading brook or water introduced by pipes among the rocks keeps up a never failing supply of moisture.
So much of the success of a rock garden, cultural as well as artistic, depends upon the placing of the stones, that one needs to proceed almost as cautiously as a Japanese extremist. Of course, the fundamental idea of a rock garden is to suggest a natural, rocky slope such as is seen on the mountain sides where alpine plants have their origin, but with its excellences condensed into a small area, its beauties emphasised by art and the number of its desirable plants greatly increased. Such a scene, however, will be of short-lived beauty unless the best possible situation and soil for every plant that one attempts to grow have been given it. It is better to devote one's first thought to providing a healthful home for the plants and then reconcile it with the loveliest pictorial effect possible. The thoughtful gardener will never pile one stone upon another without a sufficient stratum of earth in the sandwich to nourish a stonecrop, creeping phlox, or hardy candytuft (Iberis) that hangs its snow-laden stems well over rocky ledges. He will see that every rock not only rests in deep good soil and within a generous area of it, but that a pocket of loam made rich, light and cool with decayed vegetable matter -- not manure -- is provided wherever a plant is to be set out. Rhododendrons, laurel, azaleas and orchids delight in a cool, moist, peaty soil, and so do most ferns and lilies; primroses want leaf-mould; true alpines crave crushed rock or gravel mixed with it; the cross-bearing tribe and composites make the most of any good loamy soil, for they are not fastidious; hardy cacti, sedums, mossy and starry saxifrages, live forever and other more or less succulent plants, whose deep roots enable them to endure the sunniest situations, may be given a rather sandy soil without offence. Stagnant moisture about its roots no plant will endure, but then the very nature of a rock garden usually insures good drainage. Not even a skunk cabbage will thrive in sour soil. Sweetness and light are more essential in a garden than in Matthew Arnold's essays.
A SUGGESTIVE ENTRANCE TO A ROCK GARDEN.
Clinkers, shells, masses of scoria and masonry in a rockery could be tolerated only where the insensate owner would feel equal satisfaction in seeing a picket fence around it. In no other part of the home grounds, perhaps, is the suggestion of artificiality to be more studiously avoided. Walls, fences, lanterns, benches and other man-made objects should not be seen from it. Even a macadam road through it, if necessary, is deplorable. A formal path quite as effectually spoils a scene which should be entirely naturalistic, simple and picturesque. Flat, irregular stepping-stones, sunk to the level of the surrounding soil, with ferns, mosses, or little creeping plants overgrowing their edges, make the ideal path. Pebbles loosely scattered over an earth walk of flowing outline keep the feet dry, and if the edges of the path are broken irregularly by rocks over which little creepers steal out into the open, they give no offence to a critical eye. Whenever steps are necessary -- and broken levels that add so much to the charm of any garden have most reason to exist where rocks cause many uneven surfaces -- let them be made, like the path, of flat surfaced stones deeply imbedded in the earth, or grouted in cement, if there be danger of frost throwing them out of position. Steps of cedar or locust logs, that will not rot on the ground for many years, are also harmonious, but these, like the rocky steps and stepping-stones in the path, should be unequally spaced and surrounded by good soil that will encourage little plants to grow close about them and partially conceal their outlines. One feature of a rock garden in a large public park which should serve as a warning to all beholders, is, unfortunately, mistaken for an example. Rows of sharply pointed rocks, like a gigantic set of false teeth, are set along the path with a profusion of mixed magenta and scarlet portulacas among them only adding to the horror. After a long series of eliminations from gardens, public and private, one finally learns at least what not to do.
Nearly every rock garden has too much rock in evidence. Plant it out! Allow only glimpses of it here and there, unless some fine great boulders, undraped by vines, or unclothed by polypodies, or unscreened by dwarf evergreens, add a touch of nobility to the too sweet beauty of the picture you are trying to create.
A RIBBON OF CREEPING PHLOX ALONG THE BASE OF THE GRAY ROCKS BRIGHTENS THE WALK IN APRIL.
NOTE THE POSSIBILITIES WHICH SUCH ROCKY PLACES OFFER FOR A DRAPERY OF VINES. LATER, THE
LONG BARE STEMS OF THE WICHURIANA ROSES WILL BE COVERED WITH SHINY LEAVES AND MYRIADS
OF WHITE AND PINK FLOWERS.
The trace of a cutting tool on rocks can easily destroy all semblance of naturalness. Chiselled surfaces should never be exposed to view. Sandstone makes, perhaps, the most desirable setting for plants, but any rocks or boulders that belong to the region where the garden is situated are always the ones to use. Some will surely be chosen for the sake of the mosses and lichens upon them. Exquisite mosses can be cut in squares from the woods, like sods from a lawn, and successfully transplanted to carpet shady banks as if with deep green plush.
What shall be planted in the rock garden? That depends upon whether it is to be made in Maine or California, on a rich man's large estate or on the home acre of an impecunious plant-lover who is his own gardener. From the list that follows this chapter every one may make the selection best suited to his needs, but in a general way it may be said that the most expert gardener will find a fascinating hobby to tax his skill in attempting to grow the rarer alpine plants; that no better environment for many of our loveliest wild flowers, ferns, mosses, lichens and exquisitely tinted toadstools and fungi can be secured than that of a rock garden, where they properly belong; and that while many bulbs, such as scillas, chionodoxas, single narcissus and daffodils may fittingly be naturalised among the rocks, such prim, formal flowers as tulips and hyacinths look out of place in a purely naturalistic setting.
Water and rocks have been closely associated in people's minds since the miracle of Moses, and if they can be in the garden, too, the most charming results are possible. A brook, a pool, or a little cascade splashing its refreshing drops over the mossy rocks where harebells, ferns, irises, cardinal flowers, trilliums and marsh marigolds delight in them, would suggest the easy transition from earth-loving plants to those of the bog and to true aquatics. Such a gradual transition, wherever there is the opportunity to have it, insures more varied loveliness than the unaided imagination can grasp. But that is another story.
YELLOW, ORANGE AND WHITE PERENNIAL ICELAND POPPIES OF TISSUE
TEXTURE ALONG THE STEPS THROUGH A ROCK GARDEN.
FOUNDATION PLANTS FOR THE ROCK GARDEN
The flowering season given is that of New York.
ADONIS SPRING (Adonis vernalis). Yellow. April. Sun.
ANEMONE, JAPAN (Anemone Japonica). Rose, white. Single and double. August, October; 2 to 4 feet. For named varieties see trade lists. Flowers 2 inches across, like single roses. Best late flower for cutting. Partial shade. ---, WOOD (A. sylvestris). White, flowering in spring, is similar. ---, ST. BRIGID (A. coronaria, var. St. Brigid). Various colours, except clear yellow. April; 6 to 8 inches. Finely cut foliage. Like gigantic double buttercups. Most valuable species for the garden. Responds to high cultivation. ---, PASQUE FLOWER (A. Pulsatilla). Blue. April; 6 inches. Flower 1 ½ inches long, with numerous long brown hairs outside. Largest early blue flower for the rock garden.
ASTER (Aster Novae - Angliae). Purple. --- (var. rosea). Rose. --- (A. laevis). White. Best daisy-like flowers for late bloom. Variable. Sun. 1 foot up.
BABY'S BREATH (Gypsophila paniculata). White. August; 2 feet. Very small flowers in loose panicles. For shade or sun. Good soil.
BEARD TONGUE (Pentstemon barbatus). Red. July; 2 feet. Sun. In loose panicles. Flowers 1 inch long. One of the best summer flowers.
BELLFLOWER (Campanula Carpatica). Blue. July; 1 foot. Sun. ---, BLUEBELL (C. rotundifolia). Pale blue. Sun. 6 inches. These are among the very best of all the blue flowers. Easily grown, whereas the rock gentians are difficult.
BLOODROOT. See BULBOUS AND TUBEROUS PLANTS.
BLUE BELLS (Mertensia pulmonioides). Blue. April; 1 ½ feet. Shade. (See VIRGINIA COWSLIP.)
BLUE LEADWORT (Ceratostigma plumbaginoides). Blue. September. Creeping. Sun. Best creeping blue flower of summer. Like a phlox.
BLUE SAGE (Salvia azurea). Blue. August, September; 1 to 5 feet. Sun. Flowers varying to white. Light, sandy soil. Protect in winter.
BUGLE-WEED (Ajuga reptans). Blue. May. Sun. Rich soil.
CANDYTUFT (Iberis sempervirens). White. April; 4 inches. Sun. Makes tuft of dazzling white in early summer after phlox.
COLUMBINE (Aquilegia Canadensis). Red. April; 8 to 10 inches. Sun and rocky slopes. Invaluable. ---, FEATHERED (Thalictrum aquilegifolium). Pink. July; 6 inches to 2 feet. Sun. Rich, moist soil. Daintily cut foliage, with foam-like flowers.
CRANESBILL, MEADOW (Geranium pratense). Light purple. April, August. 1 to 2 feet. Shade. ---, RED (G. sanguineum). Red. August; 1 to 2 feet. Sun. ---, SPOT-FED (G. maculatum). Pink. May; 1 to 2 feet. Shade. Flat flowers; 1 to 1 ½ inches across. Common wild plants.
CROCUS, AUTUMN (Colchicum autumnale). Purple. September; 4 inches. Sun. Invaluable for late flower. Blooms without leaves.
DAFFODIL (Narcissus Bulbocodium). Yellow, lemon. April; 4 inches. Sun. This is the hoop-petticoat. Other very small-flowered species of Narcissus may be used, but are difficult to handle.
EDELWEISS (Leontopodium alpinum). Yellow. June, July; 4 to 12 inches. Sun. Small woolly flowers in star-like clusters, with very hairy bracts. Leaves also densely covered with white hair. Well-drained, medium-light soil, in full sun. Raise from seed.
EVENING PRIMROSE (OEnothera Missouriensis). Yellow. June; 18 inches. Sun.
FALSE GOAT'S BEARD (Astilbe Japonicum, var. compactum). White. May; 1 foot. Shade.
FORGET-ME-NOT (Myosotis palustris). Blue. April; 6 inches. Sun. The most pleasing small blue flower, with long season. Any soil.
FOXGLOVE (Digitalis purpurea). Purple. June; 3 feet. Shade. Rich, loose, moist soil. ---, PERENNIAL (D. ambigua). Yellow. June. Shade. Not nearly as beautiful as the common.
GOLDENTUFT (Alyssum saxatile). Yellow. April, May. Most prolific, small yellow flower of spring. Blooms intermittently all season. Self sows. Avoid heavy clay soil. Sun.
HORNED VIOLET (Viola cornuta). April till frost. Violet. Tufted plant. Flower like small pansy. Any good soil. Sun or half shade.
JACOB'S LADDER (Polemonium reptans). Light blue. May; 1 foot. Shade. Flowers half inch across in loose panicle. Much attacked by snails, especially in winter. Raise from seed in fall. Rich, deep, loamy soil.
LILY-OF-THE-VALLEY (Convallaria majalis). White. May. Shade.
MIST FLOWER (Conoclinium coelestinum). Blue. September, October; 1 to 2 feet. Sun. Flat-topped clusters on leafy stems. Any soil. Protect slightly.
MOSS PINK, CREEPING PHLOX (Phlox subulata). Rose, lavender, white. April, May; 2 inches. Cheapest and showiest carpeting plant for spring bloom. Rocks or soil, sun or shade. Named varieties have refined colours. The common wild form is a harsh magenta.
MOTHER-OF-THYME (Thymus Serpyllum). Pink. May; 4 inches. Sun. Fragrant foliage. For dry, poor soil. Evergreen.
MOUNTAIN SPURGE (Pachysandra procumbens). White to purplish. May, June; 6 to 12 inches. Shade. Shrubby. Large, dark-green leaves. Excellent for carpeting under trees. Any soil.
PLANTAIN LILY (Funkia cordifolia and subcordata). White, blue August. Shade.
POPPY, ICELAND (Papaver nudicale). White, yellow, orange, red. May; 1 foot. Sun. Raise from seed where it is to flower. Well-drained soil in sun. --- (P. alpinum). Similar.
PRICKLY PEAR (Opuntia Rafinesquii). Yellow. June; 4 inches. Sun. Exposed rocky ledges.
PRIMROSE, ENGLISH (Primula vulgaris). Pale yellow. April; 4 inches. Shade. Cool, moist, but thoroughly drained soil. Protect in winter. ---, COWSLIP (P. officinalis). Bears smaller flowers in a cluster on a long stalk. Slightly darker. ---, POLYANTHUS (P. polyantha). Like the true primrose, but in great variety of colours.
ROCK GARDEN BESIDE A BROOK IN EARLY SPRING WHEN MARSH MARIGOLDS AND HEPATICAS
ARE IN BLOOM. THEY ARE FOLLOWED BY ADDER'S TONGUE, TRILLIUMS, AND SPRING BEAUTY.
HIGHER, DRIER SITES ON THE BANK ARE THE HOME OF HAREBELLS, COLUMBINES AND
MANY OTHER ROCK-LOVING NATIVE PLANTS.
ROCK CRESS, WHITE (Arabis albida). White, fragrant. May; 4 to 6 inches. Cheapest and showiest spring-blooming white-flowered plant for carpeting the ground. Do not confuse with alpina, having smaller flowers and otherwise inferior. ---, PURPLE (Aubretia deltoidea). Purple. June, July; 3 inches. Moist or dry places. Best in rich soil in pockets to keep roots cool. Unusual colour. Needs slight protection.
SAXIFRAGE, PYRAMIDAL (Saxifraga Cotyledon). Great silvery rosettes of leaves and pyramidal inflorescence 20 inches high, of small white flowers. May, July. Largest and showiest of the family. To get the largest specimens remove the offsets. Excellent for rockeries. ---, THICK-LEAVED (S. crassifolia). Pink. April; 6 to 8 inches. Sun. Massive coarse foliage and flowers in dense, branching heads; 3 to 4 inches long. (See also LONDON PRIDE.)
SEA LAVENDER (Statice latifolia). Lavender. June; 18 inches. Sun. Any soil. Very effective. Small flowers in profuse spreading spikes. For background. Do not disturb. Deep soil.
SEA PINK (Armeria maritima). Pink. May, June; 3 to 6 inches. Sun. Flowers in dense heads above tufts of evergreen foliage. Any soil. Propagate by seed or division.
SELF-HEAL (Brunella grandiflora). Dull purple. June to July; 8 to 12 inches. Half shade. Flower heads carried above the mass of foliage. Avoid dry soil. Also for carpeting.
SHOOTING STAR (Dodecatheon Meadia). Pink. April; 1 foot. Shade. Cluster of flowers surmounting long stalk. Open, well-drained soil, moderately rich. Give northern or eastern aspect.
SHOWY SEDUM (Sedum spectabilis). Pink. August; 18 inches. Sun. One of the best summer flowers for dry, shallow soil.
SILVERTUFT (Alyssum argenteum). Yellow. April and all summer; 1 foot. In clustered heads. Sunny places with deep soil.
SNOW-IN-SUMMER (Cerastium tomentosum). White. June; 8 inches. Smothered with flowers 1 inch across. Silvery foliage attractive all season. Fine for edgings and naturalising on rocks or in strong grass. Drought resister.
STOKE'S ASTER (Stokesia cyanea). Blue. August. ---, (var. alba). White. Largest thistle-like flower for rockeries; 6 inches. Sun.
STONE CROP (Sedum hybridum, and others). Yellow. July; 3 inches. Sun. Succulent plants making rosettes of thick, fleshy foliage. For shallow ledges, growing in almost no soil at all. --- (S. album). White. July. ---, LOVE-ENTANGLED (S. sexangulare). Yellow.
SWEET ALYSSUM (Alyssum maritimum). White; 4 inches. Easiest white flower to grow for carpeting and edging. Blooms all summer on lengthening stems. Rocky ledges.
SWEET WILLIAM, WILD (Phlox divaricata). Blue. May; 1 to 1 ½ feet. Sun. Moist and well-drained soils.
TOAD LILY (Tricrytis hirta.) Brownish. Half shade. September; 1 to 2 feet. Flowers on erect, leafy stems. One of the latest bloomers. Light, sandy loam; well drained. Var. nigra blooms earlier.
WOOLLY WOUNDWORT (Stachys lanata). Pink. July; 6 inches. Sun. Valuable for the silvery foliage edging. Ordinary soil.
YARROW (Achillea Millefolium). White; var. roseum pink. September; 1 to 2 feet. Sun. Good soil.