Just as there are indoor and outdoor cats, there are indoor and outdoor rosemary plants. In their natural outdoor state they grow, thrive and perfume the air on the rocky cliffs and hillsides of Greece and the south of France, where ample sun warms the volatile oils in their needlelike leaves.
Rosemary, in most years, will survive outdoors year-round in parts of the United States that are on the warmer side of Zone 7 and higher, but this year was not one of them. Like many mid-Atlantic gardeners, a friend lost all of his despite his garden’s favorable microclimate, nestled in a hillside in Washington.
The shores of the Mediterranean may get coolness and moisture in the winter months, but not the relentless snow and ice, followed by cold and oozing mud, that characterized this winter in parts of the country. My friend plans to restock. But some gardeners find it safer to grow the plants in containers and treat them as houseplants or, as I do, make them commuter plants that go outside in spring and retreat to a sunny window in late fall.
This, too, has its perils. The late Millie Owen, in her delightful book “A Cook’s Guide to Growing Herbs, Greens and Aromatics,” wrote, “Shakespeare must have had houseplant rosemary in mind when he said it’s for remembrance: remember not to let it get dry, remember to check it for pests, remember to keep it pinched back, remember to keep a constant watch on it — and it may be happy if it’s a mind to.”
Rosemary dislikes the dim light of most indoor rooms and is unforgiving to moisture. Not enough watering will kill it. Too much watering, especially if the soil is heavy and poorly drained or the saucer is full of water, will kill it just as fast. You have to watch it and sense its needs.
I was once given a large rosemary in a decorated terra cotta pot by a friend who moved a lot. The plant then moved with me from apartment to apartment and house to house. It became a pet, increasingly ungainly and hard to please. I’ve since learned not to get too attached. In fact, with perennial herbs that tend toward woodiness — including rosemary, sage and lavender — you get the most beautiful, pliant and flavorful foliage if you start new ones each year, whether from seed, cuttings or small nursery-grown specimens.
Sited in a sheltered spot with good drainage — amend clay soil with grit and compost — a young rosemary can become a small-to-medium-size shrub in three years. If you are worried about winter survival, you can protect it during the coldest months.
Francesco DeBaggio, owner of DeBaggio’s Herb Farm and Nursery in Chantilly, Va., offers this advice: Wrap it with plastic, or any handy protective blanketing, to form a tube, but leave the tube open to the sky to receive sun, water and fresh air. After all, rosemary is an evergreen plant that does not go dormant. Cover the top of the tube if conditions become extreme, but never for more than a day.
As he points out, some varieties of rosemary are more cold-tolerant than others, especially Winter Hardy (also known as Arp) and Hill Hardy (also known as Madalene Hill). Young rosemary plants are widely available at garden centers, though DeBaggio’s is known for its more unusual varieties. For mail-order rosemary, a good choice is Richter’s Herbs at richters.com. But don’t wait until summer to shop. After such a winter, rosemary will be much in demand.
Damrosch’s latest book is “The Four Season Farm Gardener’s Cookbook”; her website is fourseasonfarm.com