The rocks for a rock garden are not usually spherical nor slab-like, but irregular in shape. The irregularity of the rocks can be complimented by more geometric wall fountains.In general, rocks should be placed with long diameter nearly horizontal (when wholly visible) and somewhat parallel to the face of the slope as if they fell to this position from the mountain peaks above. Or the long pieces may be set into the bank to lock the pile more securely. On no account should they be set with long axis vertical, for this is contrary to the process of nature.

No plants can grow on these pinnacles. You will continually stumble over them and frost or a wet season can loosen them and they fall over, to rest on choice plants. The appearance of solidity should be also reality. As each rock is put into position, it should be so locked in place by its weight or relation to other rocks that it cannot move either now or after the action of rain and frost. While the workmen are placing them, a man with heavy tread should put his weight on each.

If any slide, tilt, tip, or move in any way, they should be pulled out and reset. Repair work is difficult and exasperating after the plants have begun to grow, and yet every rock will slip which is left free to move. Here is where the workmen will offer unusable suggestions, for laying up rock gardens (for stability and desired garden effects) is quite different from constructing rubble wall with cement or dry wall with boulders. The placing of each stone is a special problem.

For stability, real and apparent, the largest rocks should usually be at the base of the pile, and those above successively smaller in size or so placed that the smaller end is visible. This not only ensures a firm position, but allows room for the plants. More than for geological truth, one must strive to suit the requirements of plants. Plants grow in soil and not in air pockets, and your skilled stone mason must do gardener's work. It is usually impossible to convince a "walking delegate" that placing stones for a rock garden is non-union labor.

No cement is ever used (except in Chinese rock gardens), and every crack and crevice is thoroughly rammed with soil. Every bit of earth has a direct connection with the soil beneath and down to the subsoil below the new construction. Poke around in the next rock garden that you visit. Likely it will be as full of holes as a prairie dog colony. Ram every crevice with soil, no matter how much the workmen grumble. This rock pile is to be dedicated to plants.

Wherever one large rock goes upon another, the poor roots would be rather squeezed unless chips an inch or more in thickness take the weight from the soil strip. Egg-like pebbles used as chinkers will give the garden a rocking, rolling motion. Save up broken bricks for flat laying and wedge-like chips for the uptilting next in order. Except in rare cases, all horizontal crevices should be far from level but sloping downward into the bank (never forward downward), with the front of the rock so tilted upwards so that rain runs easily down into the crevice.

This requirement is not of geology or of art, but for the good health of the plants. Not only should the rocks tilt back from 10° to 45° or more, but each higher rock should be set back of the line of the lower, giving the whole wall face a back slope, that each plant may have water, air, light, and room to grow. In staging this position, use judgment and vary the angle and line of the wall face, avoiding any appearance of regularity.

One enthusiastic follower of these instructions overstressed painstaking regularity and achieved the monotony of the riprap of a canal bank. All vertical fissures should be V-shaped, that the soil will rest firmly against the sides and leave no air pockets wherein roots will shrivel and die. When large crevices are to be divided, the stones should be wedge-like and dropped in large end down , which is quite unlike the usual way of burying stones, so that the fissures may be still V-shaped from above.