Extension Educator, Horticulture
Rosemary once accompanied holly and mistletoe as a popular Christmas plant. What she did to fall from favor is unclear. However over the last few years, rosemary has made a comeback as decorated topiaries. An offering of rosemary signifies love and remembrance, which is not a bad sentiment this time of year. And a sprig in your stew is quite tasty too. Rosemary is well worth growing for fragrance and flavor. She is a fairly easy going resident outdoors in the summer. The problem, however, is keeping lovely rosemary happy through the winter.
Rosmarinus officinalis is a perennial evergreen shrub hardy to zone 7, so she is not winter hardy here. In her native Mediterranean home she can reach 6 feet tall. Containerized rosemary plants can reach a huggable size. Nothing will cheer you quicker on a dull dreary Illinois day than hugging old rosemary. She is the closest thing to catnip for people. One hug and the pungent fragrance of pine will fill the air and have you rolling on the floor in delight.
Most homes are too dry and too warm in the winter to suit rosemary. She likes it cool and moist. After all, her native lands are the rocky hillsides over-looking the Mediterranean Sea.
In winter when she is fairly dormant, rosemary needs a cool brightly-lit spot indoors. She is happier if the thermostat is set to 63 to 65 degrees F or lower in a south or west exposure. A garage where the temperature doesn't drop below freezing would also work given there is plenty of light or supplemental light is provided.
Rosemary care instructions will often say, "let dry between waterings." Good advice to a point since rosemary can suffer if soil remains waterlogged. Remove the foil wrapper with decorated plants and provide a good drainage tray.
In the winter, however, the tags should say, "don't let her dry out." Soil dries quickly in our heated homes. Rosemary is not forgiving if she gets too dry. As soon as the soil dries, it's time to water. I think she does best in a soilless mix and a clay pot. Powdery mildew and spider mites can sometimes plague rosemary in winter.
Rosemary adds fragrance to the home as well as a pleasing flavor to cooking, but use the strong flavor sparingly as an accent. The flavor has been described as piney, pungent, minty, and sweet, with a ginger aftertaste. Many new cultivars have been selected for their fragrant oils and ornamental appeal. If you like the way the herb smells, you will probably also enjoy the taste. Unfortunately specific cultivars will be hard to find locally this time of year.
Popular cultivars include: 'Arp' (gray foliage, light blue flowers), 'Athens Blue Spire' (a new cultivar released by the University of Georgia reportedly hardy into USDA Plant Hardiness Zone 5), 'Joyce DiBaggio' (sold as Golden Rain and new growth is streaked with yellow), 'Madalene Hill' (also sold as Hill Hardy). Two good culinary choices include: 'Rexford' and 'Shady Acres'.
Rosemary is also one of the few houseplants that cats won't eat. Once you understand rosemary's needs, she can be a long-lived companion.