facing inward. This not only gives the wall a better purchase on the soil it retains, but also insures a good appearance. The side of the wall which faces out should be as level as possible, with obstructions and edges of outside stonesStones with round surfaces should be discarded since they do not form a good wall.

Stones should be placed in a good bond. This simply means that edges of stones on one course should overlap spaces in the lower courses. Where a stone on an upper course is crooked or does not fit firmly, earth and small stones can be packed in to improve the bond. No vertical crevices should be left.

The wall itself should slope back against the soil it is retaining. This gives it greater strength. The width of the base of the wall should be, again - as a rule of thumb - one-third of the height. It is the practice in many areas to slope the wall as much as 5 or 6 inches for each vertical foot, although this degree of slope is not essential. Soil should be firmly packed in all pockets in the wall and should be continued back into the earth being retained.

Wall Gardens

Both the strength and beauty of a dry wall may be enhanced by using it as a wall garden. It may acquire a mossy and aged appearance simply by green-planting in the soil in the crevices. A greater degree of color can be obtained, however, by planting any of several flowering plants, whose strong roots will serve the additional function of holding the wall together.

Typical plants which may be used to good effect are: such flowering types as azaleas, alyssum, evergreen candytuft, heather, phlox, garden pinks, sedum, snowy rock cress, and creeping veronicas; such spreading plants as lavender, moss, phlox and hardy verbenna; small rosettes and little tufts that need sun and room for roots like sempervivium, dwarf iris, dwarf pinks and yarrow; and the plants you can grow from seed sown among the rocks such as bleeding heart, some ivies and varieties of poppy and phlox. Sempervivi-ums, azaleas, prostrate junipers and dwarf azaleas keep a bank or rock wall green all winter.