Herbs in Winter

Madeline Wajda
Adams County Master Gardener

Those of us who cook from our herb gardens most of the year really miss those fresh herbs in the winter. However, we don't have to do without herbs in our cooking just because the garden is covered with snow.

There are several tender perennial herb plants you should have already brought in for the winter because they are not frost hardy. (If it's too late, note this for next year!) Among these plants are lemon verbena, lemongrass, scented geraniums, pineapple sage, bay laurel, and the various tender lavenders. Lemon verbenas that have been planted out in the garden can be potted up before the first frost and brought indoors. Remember that lemon verbena is a deciduous plant and will most probably drop all its leaves around Christmastime-even with lots of sun and the best growing conditions. Don't despair (and, more importantly, don't discard the plant); just put the plant in a sunny window where no one will notice you are trying to grow bare sticks. Water sparingly when dry; around mid-February you will notice the tiniest of new leaves emerging-you will soon have lemon verbena to harvest again. Alternatively, hardwood cuttings can be taken in early fall for starting new plants indoors.

Scented geraniums and pineapple sage tend to grow quite large if planted in the ground and are often difficult to bring indoors. Semi-hardwood cuttings taken in late summer or early fall root most easily in soil (a mixture of half potting soil and half vermiculite) that is at a temperature of 70-75 degrees; a thermostatically-controlled propagation mat (available in many sizes) is the best way to insure constant temperature. Scented geraniums are prone to get aphids (even in your aphid-free home); spray once a week (both sides of the leaves) with an insecticidal soap.

Lemongrass should be dug up in a clump before the first frost and planted in a pot; cut leafy tops down to about 2 inches (they'll be growing back in several weeks), keep in a sunny window, and be careful not to over water. Bay laurel can be left in a pot year-round and brought inside before the frost. It will be quite happy indoors in a sunny spot; watch for scale. If your plant should get scale, scrape it off and swab branches with a cotton swab dipped in alcohol. English lavenders get leggy and rarely flower if brought indoors; fortunately, there are various tender species of lavender (L. dentata, L. stoechas, and L. multifida) which, if placed in a sunny window and deadheaded, will bloom year-round.

Some herbs do quite well outdoors in the early part of winter. If you have savory, thyme, or sage in your garden, you can harvest from these plants until late January. Keeping rosemary over the winter can be a trial. Most rosemarys are hardy to about 20 degrees; there are a few varieties (notably Arp and Hill Hardy) that are said to be hardy to below zero. However, they seem to do best when planted against a south-facing wall in a protected area. Rosemary plants in pots do sometime survive the winter when brought indoors, although they are likely to find it too hot and dry in the house (misting helps, but don't over water). The late Bertha Reppert of Rosemary House in Mechanicsburg recommended leaving rosemary outside until after Thanksgiving, taking it "for a walk" on nice days in winter, and planting it back in the garden in March.

Chive plants need six weeks of dormancy every winter. They can be dug up now, potted up, and left outside until January. They will start to grow in about three days after being brought inside.

Many herbs can be grown in windowsill gardens, preferably in separate pots, in a south-facing window. If you don't have the right place or the right light, herbs can still be grown under a hanging fluorescent light just inches above the plants. It's best to have the light on a timer, for it needs to be on 16 hours a day, to duplicate natural sunlight. Misting once a week helps compensate for dry air in the house. Water when dry; plastic pots tend to hold soil moisture longer than clay pots. Some of the best plants for indoor culture are thyme, mint, and marjoram; there is also now a tender perennial basil (called 'Greek Columnar' or 'Aussie Sweetie') that doesn't flower and doesn't require the warm soil temperature that the annual varieties need.

With a little planning and effort, you can have many of your favorite fresh herbs at hand throughout the winter. While it may be a bit late to plan for this winter's crop, remember the seed catalogues will be in the mail soon; spring will not be far behind.

Read other articles on growing herbs or vegetables

Read other articles by Madeline Wajda