It's no secret that I haven't had much luck overwintering rosemary, one of the most pungent and often misunderstood herbs in the culinary garden.
The flavor and fragrance can overpower other herbs if too much is used while cooking. I remember making herbal vinegars several years ago and was told to go easy on the rosemary. I liked to mix herbs in some recipes, particularly if I'm planning to use the vinegar for salad dressings. The overuse of rosemary was quite apparent in the first bottle, so afterward I learned to use less.
Rosemary is misunderstood because most people think it only can be used for cooking. It can be used in potpourri, sachets and even as an addition to your bathwater as an invigorating wake-up herb.
Some say it has a scent similar to pine, but I don't agree. It definitely isn't sweet or floral, like lavender and rose, and it isn't spicy, like basil and chives. Its scent, like its flavor, is difficult to describe, but when you have it in a dish, you know you are getting something different.
Rosemary is a woody-stemmed herb. When using in the kitchen, you don't want to use the stem unless you expect to fish it out of your soup, stew, sauce or whatever dish you are making. It isn't difficult to strip the leaves from the stems. Simply hold a stem in one hand and gently pull down opposite the direction the leaves grow. Don't pull so hard that the stem will break. The leaves should come off easily.
Rosemary is easy to dry for later use. It's one of the more expensive herbs to buy in the grocery store, so rather than let it go to waste if you don't use all of it, dry the stems on paper plates or paper towels and then strip off the leaves. I prefer to store my winter herbs in the freezer. Be sure they are completely dry before freezing.
Rosemary has always been listed as a tender perennial that must come indoors over the winter. The problem I've had with the plant is that it can't stand to dry out, not even a little bit. Even forgetting to water it one time can result in a plant that turns brown and drops all of its leaves. Once that happens, it can't be revived. It also requires a lot of light. South-facing windows provide the best sun, but sometimes even that isn't enough.
Recently I've read about rosemary varieties that have survived snow and cold temperatures, including temperatures below zero. Now my interest, not to mention my curiosity, has been kindled. I consider this a challenge. Rosemary officinalis, or common rosemary, is a tender perennial, which means it can live year-round outdoors in zones 7 and warmer.
The USDA cold hardiness zone map rates the hardiness of plants based on how well they survive winter temperatures. The lower the number, the colder the climate. We have always been listed as zone 5; however, changes in the zonal map based on the average winter temperatures, have shown a slight increase in our area and has placed us on the newer maps as zone 6.
According to the Master Gardeners of Franklin County, Pa., who claim to be in zone 6 (although I don't know if this is the old or the updated zone map), there are five varieties of rosemary that can survive the winter outdoors. They are: Arp, Hill Hardy, Salem, Nancy Howard and Dutch Mill. These varieties are said to survive temperatures that reach minus-10 degrees Fahrenheit. For insurance, a little mulch or other protection from northern winds over the winter could increase the success rate of wintering-over rosemary.
If common rosemary is all that's available at local garden centers, these varieties can be found online. It's too late to put rosemary in the ground this season, but I will be looking out for these winter hardy varieties next spring and by this time next year, hopefully I will still have rosemary thriving in my winter garden.