Early July is an excellent time to collect cuttings from favorite shrubs and to root them. Azalea, camellia and holly are easy shrubs to propagate by rooting. There are several techniques for helping a cutting to form its own root system. Here is one that works for many broad-leafed shrubs:
Also see this excellent article from Fine Gardening Magazine.
1. Observe the growth which has occurred on the targeted shrub during this summer. The new growth will be 8″ to 10″ long and will have several leaves. At the base, the bark will have begun to turn from green to brown. Bend the brown growth in your hand. If it snaps, like a pencil, cuttings like it are ready to root.
2. Prepare rooting chambers from several six inch clay pots and the matching number of 2-liter soft drink bottles. Use a sharp knife, or heavy scissors, to cut off the bottom of each bottle. Fill the clay pots with a moist roooting mixture. This can be a 1:1 mix of peat moss and perlite or simply some gritty sand (Pavestone Paver Sand works well). Use a pencil to poke two 3″ deep holes in the center of the soil.
3. Take several 6″ to 8″ long cuttings from the new growth of the shrub. Strip off the leaves near the cut, leaving only a few at the tip end of the cutting. Dust rooting hormone (click for sources) on the cut end. Insert the cut end of the clippings into the 3″ holes in the potting soil. Firm the soil around each cutting.
4. Press the cut plastic bottles onto the soil surface, covering the cutting with a clear plastic dome. Remove the bottle cap. Place each rooting chamber in a shady location, where no direct sun can shine on it. Spray water through the bottle top opening to moisten the soil each week.
5. In six to eight weeks, a cutting will form roots in the soil around its cut end. Remove the top of the rooting chamber and keep the soil moist until September. At that time, the small shrub can be planted in a new area of the landscape.