Rosemary is a woody-stemmed plant with needle-like leaves that can commonly reach 3 feet in height, eventually stretching to 5 feet in warmer climates unless clipped. In zone 8 and farther south, rosemary makes a good evergreen hedge. In zone 7 and colder, try growing rosemary in a container you can bring inside in cold weather. You can even train rosemary into topiary shapes. Plants are tolerant of salt spray, making them a good choice for pots on the beach. With the right soil and water conditions, rosemary can grow into a large evergreen hedge in warm areas. Placed along a path or border, it wafts a soothing aroma to those who pass by.
Soil, Planting, and Care
Set out rosemary in spring, planting seedlings 2 to 3 feet apart; you can also plant in fall in zone 8 and south. Plants are slow growing at first, but pick up speed in their second year. While rosemary tolerates partial shade, it prefers full sun and light, well-drained soil with a pH between 6 and 7. Add a slow-release fertilizer to the soil at planting, and reapply in the spring. Or, use a liquid fertilizer like Miracle-Gro® Shake ‘N Feed® Tomato, Fruits & Vegetables Plant Food at planting and periodically thereafter. Keep the soil uniformly moist, allowing it to dry out between waterings. Mulch your plants to keep roots moist in summer and insulated in winter, but take care to keep mulch away from the crown of the plant. In the spring, prune dead wood out of the plants.
Whiteflies, spider mites, scale, and mealybugs can all bother rosemary, as can powdery mildew and root rot, particularly in humid regions. To prevent mildew and rot, be sure your plants enjoy good drainage and air circulation. In zone 7 and northward, extreme cold will kill the tops of the rosemary plant. In areas where it is likely to be hurt by winter, plant in a protected spot such as one near a south-facing masonry wall and away from the prevailing winter wind; also mulch to protect the roots. In zone 8 and farther south, rosemary needs no winter protection.
While rosemary blends well with other herbs, use it lightly on its own in lamb, pork, chicken, and veal dishes, as well as in soups and stews, vegetables, and sauces. Rosemary provides a wonderful flavour in breads and makes a good marinade with olive oil, wine, and garlic. Rosemary’s aromatic qualities also enhance a bath, bouquet, wreath, or sachet.
Will rosemary grow with the other herbs in my herb garden?
Unlike most herbs that live for only one season, rosemary is an evergreen shrub in zone 8 and farther south. For that reason, you should choose a location where it can continue to grow for years to come. It thrives in a sunny, well-drained location where it will reach up to 3 feet tall and wide. You can place it near the gate to your vegetable garden or as part of your home landscape. Because it is so fragrant when touched, it is a nice addition near a sidewalk or porch.
What is rosemary's temperature tolerance?
Our rosemary is dependably hardy in USDA zone 8 and southward, which means in areas in which the temperature does not go below 10 to 15 degrees. If you live in zone 7, plant in a protected location, such as near a south-facing masonry wall, to provide added warmth on cold nights.
Can I trim rosemary anytime, or is there a recommended time?
As with any culinary herb, you should cut fresh, flavorful foliage whenever you need it. Plants do well with a heavy pruning anytime from early spring to midsummer. Try not to cut into stems that are dark and woody; these are less likely to sprout new growth than the younger wood. Remember that rosemary will never have a perfectly round silhouette, because it is the nature of the plant to have upright stems. However, the overall habit of the plant can be thicker with pruning to encourage branching.
I grew rosemary in a large pot and left it out over the winter. Should I cut the plant back or wait for new growth?
Early spring before growth begins is a good time to prune any evergreen, and that includes rosemary. Remove any dead, leafless stems first, and then prune to improve the shape of the plant. Avoid cutting stems that are very old, as they may not sprout new shoots are readily as younger stems. However, if your plant is nicely shaped and you are happy for it to continue growing larger, remember that pruning is not a necessity. Note: when rosemary is grown in a container, do not let it dry to the point of wilting. It may not recover.