Varieties of Rosemary Herbs

Cultivar Characteristics

• Rosemary cultivars come in a wide variety, with at least 51 grown by the U.S. National Arboretum. Cultivars differ in form, cold-hardiness, the color of flowers and even the fragrance. Most cultivars will have blue flowers, but pink and white also are present on some varieties. Rosemary scents vary from a strong pine to no scent at all, and shapes include creeping, sprawling, prostrate or upright. The leaves of a rosemary shrub may be broad or short, thin or stubby.

Popular Cultivars

• A popular variety for indoor planters, Blue Boy rosemary only grows to 2 feet, which is a full foot shorter than regular rosemary. Blue boy is known for its flavor and freely blooming flowers, but only can be propagated by cuttings. The two most commonly grown rosemary cultivars in the U.S. are arp and hill hardy, which are known for their cold-hardiness. Tuscan blue and prostratus rosemary are known for their slow-growing speed and creeping plant styles, while gorizia has courser leaves and albus produces white flowers.

Cold-Resistant Cultivars

• If you are growing rosemary outdoors and have some nights with below-frost temperatures, you may need to take precautions against the cold, according to the U.S. Department of Agriculture. The two most cold-hardy are arp and hill hardy, but a handful of others are also safe. The U.S. National Arboretum recommends a variety of cold and twig dieback-resistant rosemary cultivars, including Albus, Bendenen Blue, Goodwin Creek, Herb Cottage, Light Blue, Miss Jessup's Upright, Russian River or Salem.

Tips

• If you want a cold-hardy specimen of rosemary, the U.S. National Arboretum recommends looking for a plant with thin leaves and light-colored flowers. Prostrate cultivars tend to be the least cold-hardy. Rosemary should be planted in the spring in an area that receives plenty of light and minimal wind. When harvesting rosemary, dry the sprigs on a screen and then store in an airtight container.