The Following is an excerpt from the Book "Patio and Stone" by Tom Wilhite on Page 151 (I really like how they broke down the Importance of boulders in Masonry Design):
Depending on their shape and how they're placed, boulders can serve many different purposes in a garden. Wide, low stones may be seen as anchors, perhaps nestled beneath the boughs of a low-branching tree. Tall thin stones might serve assentinels flanking the entrance to a path.As landscape architect Karen Aitkenpoints out, "Boulders can be a unifyingelement in an informal design, servingas turning points in a walk or lawn edgeor even acting as camouflage forirrigation, hose bibs, and electricalboxes."
Generally, boulders look best if they'replaced the way they would appear in thenatural landscape. Consider taking adrive or hike to observe stone. In nature,you'll find like kinds of stones groupedtogether, so follow that example if you'reafter a natural look. Outcroppings ofboulders usually run in parallel bands, so when you're placing several stonestogether, line them up so that anystratification runs in the same direction.If layers aren't obvious, position thestones so that their top surfaces all tiltat the same angle. Several small stonescan be made to look like pieces of a hugeboulder by grouping them fairly closetogether, with their most jagged edgesfacing up. If a boulder breaks apart whileyou're installing it, so much the better;just leave the pieces with the brokenseams parallel.
Boulders are rarely found sitting ontop of the ground; they typically rise outof the ground, often with just a tip orone or two faces showing. To get thiseffect in your garden, bury stones up totheir widest point or with a third to ahalf beneath the soil. If one side of theboulder has moss or looks weathered,that side should face up. Gardendesigner Tara Dillard advises studyingeach stone carefully: "Boulders speak.They tell you which is their front, top,and side face, how deeply they should beburied. An old Chinese saying gives goodadvice for placing two stones: One, themale, should reach toward the sky andthe other, the female, should lie with theearth.'
Long thin boulders can be placed flat,perhaps serving as a bench or a low wall,or planted upright as a vertical accent.As landscape designer Scott Colombonotes, "Tall columnar boulders can bespectacular in the garden, but theirplacement should make sense and notbe willy-nilly. A natural-lookingarrangement might include one uprightcolumn and a couple of large flatboulders that double as benches." For astone column to stand securely, aboutone-fourth of its height should be belowground. Dig a hole that matches theshape of the stone's base so it will bestable and add smaller rockS into thehole to lock the boulder into position.For very tall columns (over 6 feet), setthestone on a concrete pad in a holethat is one-third the length of the stoneand three times its width. Fill in withcrushed gravel, tamp it down firmly every6inchesor so, then add 4inchesof topsoil. "
Brick House Stone Masonry 309 Clarence St. London, Ontario N6B 2K2 (226) 781 - 1046