Rosemary features dark green foliage and pale, purple-blue flowers that are perfect for a fragrant garden hedge or a holiday topiary. But it isn’t just grown for aesthetic purposes—the savory, piney taste can elevate the flavor of a variety of foods, and growing this herb fresh pays off in the kitchen.
Rosemary is a perennial, so choose a long-term location with plenty of sunlight, prepare the soil well, and plan for weed control. Plan ahead and select an upright variety (up to 6-feet tall) or a mounding or cascading shape that suits your growing space.
Growing From Seed
Rosemary is rarely grown from seed, because germination takes months and has a poor success rate. While it may be an interesting gardening challenging, we recommend starting from a cutting.
Growing From a Cutting or a Starter
You can grow rosemary from an existing plant you particularly like. In spring, take a 3-inch cutting where there is soft, new growth. Strip off the leaves from the bottom half of the stem, leaving half a dozen at the top. Insert the stem gently into potting soil and water thoroughly. Place the cutting in a bright window, not too hot, and keep moist for about 8 weeks. When you see new growth on the stem, that means roots are growing in the soil, and it’s time to transplant.
The Texas A&M Agrilife Extension recommends clearing stones and debris from your planting location and adding 4-6 inches of compost. Work it into the soil, and then form a mound for each plant to ensure good drainage. Dig a hole as deep as the plant’s root ball and twice as wide, then plant, water, and mulch.
Growing in Containers
After the plant has been transferred to a larger pot and new growing medium, you can pinch off soft growth to even up branches and shape the plant as it grows. You can also try providing some nitrogen-rich fertilizer to the potted plants.
Rosemary is a low-maintenance, woody perennial that can last for many years if protected from freezing temperatures, watered regularly, and thinned occasionally.
Light, Temperature, and Humidity
Rosemary comes from the Mediterranean climate, so by nature, it wants a full day’s sunshine and warm weather. Outdoors, it is very adaptable to hot, cool, dry, or wet weather. Indoors, on the other hand, rosemary may become dry and turn brown. Place the pot on a tray filled with
pebbles and water
to maintain the plant’s humidity and giving the plant a sunny but cool location.
Soil, Nutrients, and Water
Rosemary thrives in soil with good drainage, as too much water can lead to rotting roots or a very woody, tough-looking plant. It requires very little extra nutrition, but an all-purpose food with a regular amount of nitrogen will help it add new vegetative growth.
Some varieties of rosemary are drought resistant or at least water-smart, requiring only a good soaking once a week, but in very hot places rosemary can use more regular watering.
Rosemary is evergreen in climates warmer than Zone 6. In very cold zones, plants should be grown in pots and moved indoors before frost bites them. However, if that is not possible, try pruning the plant to just 5-6 inches above the ground and covering it with a thick layer of straw mulch for insulation. If your ground freezes solid in winter, even this is unlikely to work.
Common Pests and Diseases
Rosemary is fairly disease-resistant, but if powdery mildew or similar diseases appear, apply an organic fungicide. Few insects bother this plant. Treat spider mites and other pests with a soap-based spray, and scale insects—those sedentary sap-suckers that look like barnacles—by pruning and discarding infested branches. Most troubles can be avoided by thinning plants, not overwatering, and fertilizing just enough.
Some varieties have a stronger-smelling mix of aromatic compounds, including pinene, a distinctive-smelling type of terpene found in pine trees and other plants. The broader, flatter leaves seem to have less of the pine flavor and more culinary balance, compared with others whose appeal is primarily decorative.
Tuscan Blue grows bushy and upright with dark leaves, tolerates hot weather, and has an excellent, balanced flavor,
Arp is cold hardy to Zone 5 and drought resistant, with light blue flowers. It grows upright with straight branches that make good barbecue skewers.
Irene, a cascading type, is drought resistant and provides lots of flowers.
How to Harvest, Store, and Preserve Rosemary
If you harvest more than a few cuttings at a time, take the opportunity to prune strategically for enhanced air circulation and growth, then let new shoots fill in before harvesting again.
Rosemary can be used fresh , frozen, frozen in olive oil, or dried. To dry, hang small bunches of rosemary upside down to dry and then remove the leaves and store them in a glass jar.