Bay trees, also called bay laurel (Laurus nobilis), are the source of bay leaves used in the kitchen to flavor soups, stews and sauces. The trees can grow as tall as 40 feet or more, although normally they are pruned to be much shorter and more compact. The easiest way to propagate a bay tree is by layering, or partially burying an attached stem until it develops roots. If that's not practical, you can also propagate a bay laurel by taking a cutting and rooting it in soil, although you may only have marginal success.
Fill a six-inch-diameter pot with a blend of equal parts of all-purpose potting mix and compost. Make sure that your pot has a drainage hole on the bottom.
Use a sharp knife to cut a four- to six-inch-long stem from a bay tree. Gouge the knife into the main trunk a little bit when taking your cutting, so that the stem appears to have a "foot" or a "heel."
Remove all but the top four leaves of the cutting.
Plant the cutting so that the heel is about two inches below the soil surface. Water the cutting thoroughly.
Place the pot on a heated seed mat. Bay trees require warm temperatures to thrive and put out roots. Do not use heating pads designed for human use.
Place an open plastic bag loosely over the potted bay tree to retain moisture and create a humid environment.
Keep the newly planted bay tree away from direct sunlight.
Water as needed to keep the soil evenly moist, and check on the cutting regularly to make sure that mold isn't developing on the soil's surface. It may take up to a year for a bay tree cutting to put out roots.