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Rock garden design

Rock garden designThere is seldom a choice in selecting a natural setting for our rock garden, and this is especially true among little gardens, but we may have a rock garden any place provided that there be good drainage, light, pure air, and a healthy soil.

A rock garden does not mean a "rockery." We might define a rock garden as a flower garden containing a few natural, weather-beaten rocks, so arranged that they look like a natural deposit. A "rockery" might be classed as a grotesque mass of rock containing a few ill-arranged pockets of soil which attempt to support the life of a few sickly plants.

We may take advantage of nature's rock deposits and add a little beauty and colour to this rugged bit of landscape by planting a few choice rock plants and dwarf evergreens in the pockets of soil between the rocks. Great care should be taken not to mar the already existing beauty by some artificial attempt at gardening.

After selecting the site for our rock garden we may consider constructing a rugged path of natural flat stone which may lead into a recess, shaded by tree and shrub. Whether the path has been long or not, you will welcome the stone seat; and the less pronounced or finished this leading path is, the more secluded and quiet the place will seem.

If the seat be made of large stones and the junction of the stone and soil is natural, it will serve to suggest that the construction is not artificial. No chisel should be allowed to touch the stones, and the material used should be weathered attractively. The stones should be common to the locality, for there is nothing more inappropriate in the treatment of a naturalistic landscape than a finished granite seat where all about are rocks of a different type.

Before constructing this rock seat, remove the soil to a depth of from one to two feet and fill in the area with large stones, thus forming a solid foundation over which the seat is to be built. Rocks laid on the surface soil are seldom firm. After the seat is completed, plant shrubs and plants common to the locality with the view to making the completed work look as though man had had little to do with this addition to the garden. When possible, leave out a rock here and there, leaving a space slanting downward toward the base or foundation, and fill the hole with a rich soil. Plant Arabis alpina and Arabis albida or Linum flavum in these spaces.

It may be that you wish to cross the stream just beyond the old friendly Willow tree, and here again rocks may be used to great advantage. The bridge should have a strong foundation to offset the crushing weight of ice in the spring and the action of water during the rest of the season. The stone used in this structure should never be faced, and the cement should not show. The stone may slant in any way you wish on the top of the bridge and close to the bank, but the large stone that forms the bottom of the bridge should be parallel with the water and close to it. A few conspicuous, bold stones always add to the beauty of such a rustic bridge.

Whenever a bridge, summerhouse, stone seat, or steps are constructed, a cement properly mixed to give firmness and durability is of greatest importance. For strong and impervious work, especially for a bridge and summerhouse constructed of stone, use one part cement, two parts sharp sand, and four parts gravel or crushed stone.

Along the bank and in large groups should be grown Ferns such as Aspidium thelypteris, Onoclea sensibilis, both growing 12 inches high; Osmunda regalis, growing 2 or 3 feet high; Woodwardia virginica, growing 2 or 22 feet high. There are also a few flowers that, if grouped, look well, especially near the water, such as Lobelia cardinalis, growing from 18 to 36 inches; Iris verna, 4 to 8 inches; Iris cristata, ¢ to 8 inches; Lilium philadelphicum, 12 to 24 inches. Flowering shrubs and evergreens may be massed high up on the bank.

If the water is sluggish in places, a few Waterlilies add greatly to the attractiveness of such spots. A place where the shrubs and Ferns are mirrored in the water may suggest a summerhouse. Where the land is rough and rocky, a summerhouse constructed of stone and covered with any one of the following vines will harmonize with the landscape as well as lend comfort and pleasure: Ampelopsis quinquefolia (Virginia Creeper) ; Celastrus scandens (Bittersweet), or Clematis paniculata.

Before planting the vines near the summerhouse foundation, prepare the soil to a depth of at least two and one half feet. The sun on the stone takes a lot of moisture out of the soil, and usually the soil in a rocky place is poor and shallow. The hole should be at least two feet in diameter and the soil best suited to the desired vine filled in. The three vines suggested will not thrive in a stiff clay or pure sand. Dig a hole two feet in diameter and two and one half feet deep. Fill the hole with two thirds garden loam and sod chopped up fine, one third decayed cow or horse manure, and a sprinkling of coarse bone meal thoroughly mixed. Bittersweet will thrive best in a soil that is one fourth leaf mould, one half garden loam and sod, and one fourth well-decayed stable manure.

Fragments of rocks, particularly flat limestone, are often used to construct steps up a steep incline or a slightly sloping hill. The stones should be placed unevenly, not in a straight line, and fitted into the incline so that they are level. Back from the edge, but sufficiently forward to support the front of the step, should be a stone support or foundation to prevent it from tipping forward. Six or eight inches of coarse ashes should be fitted into the back and under the rock to prevent heaving from frost and to insure drainage. The ashes should not be brought so near the side edges of the steps that the plants are made to suffer from drought during the heat of summer.

The steps should always look secure but natural. In the perpendicular space between the steps, which is from eight to ten inches, one should leave pockets, particularly near the side edges, in which there should be placed from six to ten inches of rich soil. In these pockets plant Androsace alpina, Sedum acre, Erinus alpinus, Saxi­frage, and such Ferns as Asplenium trichomanes, 4 inches; Yoodsia obtusa, 9 inches; Woodsia ilvensis, 5 inches. Here and there two stones in the same step may be left separate for a space of from one to two inches. This space should be packed with rich soil to 'a depth of six inches at least, in which grass or moss may be encouraged to grow.

If the steps are located in a partly shaded place, large clumps of Azaleas, Rhododendrons, Andromedas, Erica in variety may be planted close to the steps and allowed to encroach on the sides of the steps. Here and there on the edge of the steps such plants as Arenaria balearica, Erinus (in variety), Linaria pilosa are pleasing. There are many combinations of flowering shrubs and evergreens that may be planted unevenly and in large groups along each side of the steps or possibly only on one side. Allow the grass and a few natural wild flowers to fit into the steps on one side, and banks of shrubs added on the other side will make a most attractive touch to the landscape. The planting should never be in straight lines, but should be carried out in such a way as to hide any suggestion of artificiality.

The following list will do well in a shady place on a fairly dry soil and may be fitted beautifully into the rocks: Aspidium marginale, 1.5 feet; Aspidium acrostichoides, 1 foot; Dicksonia punctilobula, 1.5 feet; Osmunda clay­toniana, 2 feet.

If the fern rockery is in the open, the following Ferns will do well in the sun: Onoclea struthiopteris, 3 feet; Osmunda claytoniana, 2 feet; Dicksonia punctilobula, 1.5 feet; Asplenium felix-foemina, 2 feet.

The following five Ferns are among the most beautiful of the low evergreen Ferns for a rockery in the shade: Asplenium ebeneum, 10 inches; Asplenium trichomanes, 4 inches; Camptosorus rhizophyllus, 4 inches; Polypodium vulgare, 6 inches; Woodsia obtusa, 9 inches.

If the rock ledge is in a dry place the following four Ferns will stay green throughout the season: Asplenium trichomanes, 4 inches; woodsia obtusa, 9 inches; Poly­podium vulgare, 6 inches; Woodsia ilvensis, 5 inches.