Rosemary is a tartly scented, perennial growing herb that has been in cultivation for centuries. Generally used as a seasoning in creating various dishes such as lamb and pork, rosemary is typically used in small planters and as a hardy centrepiece to many herb gardens. Used as a hedge, rosemary makes for a dense, thick mat of evergreen growth. The flowers are small, about 1/2 inch in diameter and are usually in the white to light-blue colour range. Depending on how high you wish to grow a rosemary hedge, it can require between 2 and 4 years before maximum height is achieved.
Choose a full-sun planting location for the rosemary hedge. Rosemary requires excellent drainage and warmth; avoid shaded areas and low-lying areas.
Measure how long you wish to make the rosemary hedge. This depends on how much room you have in your garden.
Turn over the soil in a 3- to 4-foot-wide section down the entire length of the planting area. The soil should be loosened to a depth of approximately 18 inches.
Dig a hole about 10 inches deep by about 10 inches wide. You will use this hole to check on the drainage ability of the garden soil. Rosemary needs quick-draining soil and cannot tolerate soggy roots. Once you have filled the hole with water, let it sit for no more than 30 minutes. If there is any water left standing in the hole, you need to create a raised planting area for the rosemary.
Spread out a 3- to 4-inch layer of amendment across the topsoil if the results of the soil test indicated there is less than ideal drainage of the soil. You can use leaf mould, aged cow manure, peat moss or any similar type material. If you do not need to create a raised planting bed, you can mix the amendment 12 to 16 inches into the soil.
Measure out the spacing for how far apart the planting holes will be. For creating a dense hedge, measure out the holes about 12 to 14 inches apart. For a looser, less thick hedge, measure the holes about 16 to 20 inches apart.
Remove one of the rosemary plants from its planting pot. Lay the pot sideways on a bench or the ground. Push down on the rim until you can free the pot from the root system.
Place a rosemary into the planting hole. Hold it level in the hole as you scoop soil into the hole until the hole is about 2/3 full. Firm the soil around the root system then fill the remainder of the hole with soil.
Water each rosemary until you are sure each plant has been thoroughly saturated. Avoid over-watering the plants, water with about 1 inch of water weekly.