Planting an herb garden rewards you with fresh-grown herbs for cooking and aromatic plants for your garden. Rosemary is a smart choice for any garden, but weeping, or prostrate, rosemary (Rosmarinus officinalis "Prostratus") is especially versatile. Weeping rosemary can grow as a potted houseplant, or outdoors year-round in U.S. Department of Agriculture plant hardiness zones 8 through 10, depending on the cultivar.
Weeping rosemary gets its name from its trailing growth habit, which differs from common rosemary, which is an upright plant. The weeping type sends out stems that can extend 8 or 10 feet in any direction from the plant's base. When used as a ground cover, weeping rosemary usually reaches a height of 6 to 12 inches. When planted in the soil at the top of a wall, its stems cascade down the face of the wall and, if container-grown, the stems spill over the edge of the pot and hang down gracefully.
Weeping rosemary has fragrant bluish-green foliage and abundant, pale blue flowers in early to midsummer. It grows and flowers best when planted in full sun, although it can tolerate a few hours of partial shade, especially in areas with strong, hot summer sun. When choosing a planting site, it's best to avoid areas that are extremely humid or tend to stay wet and moist for long periods. Although it does well in a spot that receives an average amount of water, it also tolerates short dry spells well. Weeping rosemary needs good drainage for best performance, so if you soil is high in clay and drains poorly, add some sand at planting to improve its drainage.
Pruning and Problems
As weeping rosemary grows, stems that are nearer to the ground or covered by other branches can become shaded and might dry out and lose foliage. Pruning these away each year or two stimulates new growth and helps keep the plant looking tidy. This is best done by carefully lifting the plant's long, outer leafy stems to access the older stems and cutting these back if they appear dry and unproductive. Weeping rosemary is usually pest- and disease-free, but can develop root rot or other fungal problems if grown under excessively moist conditions. Watering at the root zone with a soaker hose to keep foliage dry and clearing debris from under the plant regularly helps minimize these problems.
Several different cultivars of weeping or prostrate rosemary are available at garden centers and nurseries. These include "Blue Lagoon," which grows about 16 inches tall and has dark blue flowers in spring, and "Blue Rain," with masses of long-lasting, pale blue flowers on 2-foot-long stems. These two cultivars grow in USDA zones 8 through 11. A variety called "Boule" has green leaves with white undersides and medium-blue flowers, while one called either "Renzels" or "Irene" has profuse, long-lasting, violet-blue flowers in summer. "Lockwood de Forest" is an especially vigorous cultivar, with arching branches and showy, lavender-blue flowers. These three varieties grow in USDA zones 8 through 10.