Summer is a great time to propagate favorite shrubs by rooting stems underground. This is one of the simplest ways to multiply a shrub and it is fast and efficient. Start by looking for long shoots which can be bent to touch the ground. Measure eight to twelve inches back from the tip and dig a narrow trench in the ground under that area. Take a dull kitchen knife and gently scrape the outer bark from the shoot there for one or two inches.
Sprinkle a bit of rooting hormone (Rootone, etc.) on the injury and lay it in the trench. A few leaves should emerge from the end of the trench. Cover the stem with moist earth and place a brick on top to keep it buried. A length of orange ribbon tied around the brick will remind you where you were working.
In two months, cut the stem connecting the stem to the mother plant. In November, the stem will have fully rooted underground and can be transplanted to another spot.
SOIL LAYERING Hank Bruno, the trails manager at Callaway Gardens, taught me a quick and effective way to root plants where they grow. When he sees a beautiful azalea or other notable shrub, he bends a branch down to touch the earth. The touch-point should be twelve inches back from the tip of the branch. Using the blade of his pocket knife or a handy stone, Hank gently scrapes the branch where it touches the soil. He mounds a fistful of dirt over the wound and places a brick on it to hold it touching the ground.
By spring, roots have formed from the wound and Hank can clip the baby plant from the mother and transplant it into gallon pot.