Horehound (Marrubium vulgare) is a European herb that has been used medicinally since antiquity. It's a perennial in the mint family. You can start your horehound plant from seeds or cuttings---early spring is the best time to get it going. It spreads rapidly in most climate zones. A tea from the fresh leaves and flowers is used for lung congestion of colds, flu, laryngitis or other bronchial ailments. Horehound's dried leaves and flowers add a nice scent, beauty and interest to dried arrangements and you also can store them to use as tea during the winter when your plant is dormant.
Fill pots or flats with standard potting soil in fall or spring and then sprinkle the surface with water.
Scatter horehound seeds on top of the damp soil and then press them gently into the soil with your palm. If you are using a rooted plant division, poke a hole large enough for the roots and then pat the soil down around its base.
Transplant 1-inch seedlings into individual 3-inch pots using the same type of potting soil you used to start your seeds.
Transplant your young plants to a sunny spot in your garden in spring when they are 3 to 4 inches tall.
Dry horehound by collecting small bundles of the fresh plant and hanging them in a warm, dark, dry, well-ventilated place, such as your garage. Then store it in sealed jars you keep in a dark place.
Make tea from either the fresh or dried plant: Place about 3 tablespoons of the chopped leaves and/or flowers into a teacup and then pour boiling water over it. Allow to steep for five minutes and then sweeten with sugar or honey to taste.