- Rosemary: A Robust Herb of Winter
- Plant Hardiness Zones
- Protecting Plants from the Elements
- Potting-Up to Bring Indoors
- Rosemary for the Spring
- Suggestions for Keeping Rosemary Alive Over the Winter
- The Essence of Rosemary: Help Rosemary Survive Winter
- More about rosemary on Garden Making
Rosemary: A Robust Herb of Winter
- The spiky needles of rosemary add robust flavor to winter dishes.Photo/Illustration: Susan Belsinger
- Rosemary (here overshadowed by bay) can be grown in a raised bed.Photo/Illustration: Susan Belsinger
- A Mediterranean herb garden in Texas, where rosemary grows outdoors year round.Photo/Illustration: Susan Belsinger
We cannot claim positively that any herb lightens doldrums or depression, but we are always cheered when we brush rosemary leaves through our fingers to release its refreshing scent. Its quintessential fragrance of seacoast with pines affects us like an offshore breeze at early evening. The drears and dulls are blown away, even if we are miles from the sea and enduring the freezing days of February.
The Romans transplanted rosemary to England, where the sea-saturated climate of the south was mild enough to favor it. The name is from the Latin ros marinus, dew of the sea. It flourished through the Medieval and Renaissance periods, every garden having its single or several bushes, often pruned in fanciful or symmetrical shapes. Some favorite uses of the essential oil, or the leaves and flowers, were in refreshing baths, as an insect and moth repellent, as a mouthwash, and in liniments.
|Country Pea Soup with Rosemary makes a fine winter supper. Get the recipe…|
Rosemary is not as popular a culinary herb in the U.S. as in Europe. In Italy, where it is much loved, a sprig of rosemary (and sometimes a branch of sage as well) are commonly included with purchases at butcher shops in Northern Italy. Italians consider it excellent with roast meats, poultry, and fish. Branches of rosemary are usually put on the coals when lamb and kid are roasted. It is also used in stews, bean dishes, with potatoes, and in certain sweets. It is also served with the cheese course, in lieu of dessert, chopped fine and strewn over Pecorino cheese drizzled with fine Tuscan olive oil.
Rosemary’s aroma is a combination of fir, balsam, and ocean air. Its components of tannin and camphor give it a moderate bitterness and pepperiness, which are especially good with foods rich in fat or with bland foods, such as potatoes or legumes. For some, the flavor of rosemary is very strong, but its champions like the warmth and richness it gives to hearty dishes and its spiciness with more delicate fare. Dried rosemary may be generally used for fresh, with the exception of use with cheeses.
Rosemary must be dried in the whole needle to preserve its oils, but it should be ground or tied in cheesecloth to prevent the sensation of chewing on pine needles. The strength of the dried herb varies greatly, but commonly the amount used is one-quarter that of fresh.
How to grow rosemary
|Rosemary grows well in containers.|
Although rosemary is a true Mediterranean plant and will not survive extremely cold winters, it can be grown in pots with the following care. Keep the plants in appropriately sized containers, transplanting as necessary. When transplanting, allow plenty of room for the roots. Use a mix of perlite, large-grained sterile sand granite dust, and/or chicken grit for good drainage and aeration along with a combination of humus and potting soil to make the best mix for growing Mediterranean herbs.
Set the plants outdoors in the summer, taking care to water them well. About one month before the first frost is expected, bring the plants to a protected area near the house. I keep my rosemary plants in a protected spot near the house and only bring them indoors when the temperatures are going to drop to below 30°F. Then I bring them into my greenhouse, which is passive solar, so it is fairly cool in there. They are better off outdoors with fresh air until the last minute rather than indoors with dry heat. Rosemary loves light and this need must be met in the house or garden. I move them back outdoors as soon as the really cold weather has passed—usually in March in my zone 7 garden.
|A floating row cover offers winter protection to rosemary.|
For those of you in warmer climes, you are lucky to be able to grow your rosemary outdoors year round. You can see in the photos how they thrive in Texas. There are a few hardier varieties that you can try to winter over in central U.S. such as ‘Salem’, ‘Hill Hardy’, and ‘Arp’, but I haven’t found anyone who was able to winter them over outdoors in the northern states. If it is going to be very cold with freezing temps, we wrap our rosemary plants with a few layers of Reemay (floating row cover) to keep them from freezing and drying out. This has worked for us so far and we were able to bring them through a long, cold winter.
Above: Rosemary features prominently in a Mediterranean herb garden in Round Top, Texas.
At left: a bay shrub and a sprawling rosemary plant in a Texas raised bed garden.
A cutting is the best way to start rosemary, as seed germination is slow. Rooted cuttings are generally available from herb or nursery suppliers. Rosmarinus officinalis is the herb to buy for culinary use, and the easiest to grow. There are a large number of varieties of R. officinalis, and from the cook’s point of view all can be used successfully—thin or thick-leaved, pink or blue-flowered, and pine-scented. All rosemary types are good for cooking. The varieties have different aromas, slightly different flavors, and quite different physical characteristics, such as plant and leaf size, variegation, flower color, and cold-hardiness; become familiar with them to discover which ones you like.
|‘Prostratus’ rosemary in full bloom.|
Water and mist rosemary regularly, and fertilize every couple of months, both outside and inside. Reduced sunlight and lower daytime temperatures in the house lessen the need for water; let the plants dry between watering.
In temperate gardens rosemary does very well against brick or stone. Some magnificent plants can be found growing against walls and barns in the southern U.S. and the Mediterranean region, where the plants spread by layering. It grows nicely as a freestanding shrub but requires more attention to avoid a straggly look. It can become a hedge if given the proper growing requirements. A low-growing tender variety, R. officinalis var. prostratus, makes a fine ground cover, growing from 10 to 12 inches tall and spreading easily.
More robust herbs … • Using Sage in Warming Winter Dishes
• Outstanding Oreganos and Mild-Mannered Marjoram
• Thyme, a Robust Herb of Many Uses
• Savory for Winter Dishes
If you have rosemary growing in your garden, you might be wondering if it can survive the winter outside.
Fortunately, there are measures you can take to protect your plants from the cold, and have them come back healthy and vigorous in spring.
Let’s see what we can do.
Plant Hardiness Zones
A big factor in determining if your rosemary will survive the winter outdoors is your USDA Plant Hardiness Zone.
This herb is usually fine in the garden during the cooler weather in Zones 8-12. However, if you live in Zone 7 or below, it’s quite possible your plants will die if you leave them outside during the cold season.
Protecting Plants from the Elements
If you live on the edge of rosemary’s winter survival zone, in Zone 8 or 9, you’ll need to provide extra protection for your plants if you want them to overwinter outdoors.
One option is to cover them with floating row covers. This can act as a blanket and keep the air temperatures around the plants a little higher.
To do this, drape the cover over your plants, making sure there are no gaps between the ground and the material.
Secure the cover at the sides with dirt, bricks, or other weights. Gather each end to close and then weigh them down.
Another option is to prune and mulch your plants right before temperatures dip below freezing.
Using pruning shears, cut the green foliage down to about six inches tall.
Then cover the whole plant with a mulching material such as straw, leaf mold, or wood chips. This will provide protection from the drying wind and cold air.
Mulch also protects the soil from cycles of freezing and thawing, helping to keep soil temperatures stable. This allows plants to stay dormant over the winter months without sustaining damage to their roots.
You can read more about mulching to protect plants in winter here.
Potting-Up to Bring Indoors
If you live in Zone 7 or below and your plants are growing in the ground outside, you’ll need to pot them up and take them indoors away from the cold.
You’ll need to dig up your plants before the first frost has a chance to do any damage. So any time during the autumn you can move them into containers ready for the winter.
To dig up rosemary, you’ll need a shovel. In order to keep the plant healthy, it needs a large intact root ball.
Depending on the age of the plant, it can develop quite an extensive root system, and the more of this you can keep, the better.
Dig at least six inches away from the main stem. Continue moving around the plant until you have a circle that is a least a foot in diameter and a foot deep, depending on the size of your plant.
Carefully lift the plant and the root ball out of the ground, shake off some of the excess soil and place it in a large container. Add soil around the root ball and pat down gently.
Leave the plant outside for a few days to acclimate to its new container, provided there is no frost in the forecast.
A sheltered spot on a patio or balcony would be ideal. Alternatively, if you’ve got some bad weather on the way, a garage or basement would keep it safe from the elements.
You can then move it inside.
It’s best to keep the plant in a location where the temperature is above freezing, but not too hot.
A lightly heated garage or hallway is a good option, as warm indoor air can cause the plant to dry out. Rosemary likes a bit of humidity, so gentle misting of the foliage can help keep the air around it moist.
Water lightly about once a week. Make sure you don’t overwater, as rosemary hates sitting in wet soil. Growth will slow right down over the winter, but there’s a chance you can still harvest a few of the leaves.
Once the temperatures start to warm up, you can move your pot outside during the day to gradually acclimate the plant to the outdoors.
When all risk of frost has passed, you can either choose to replant it in the garden, or keep it growing in the container.
Rosemary for the Spring
If you follow the methods listed above, you’ll give your rosemary the best chance of surviving the winter.
Once spring arrives, you’ll have a fresh supply of this fragrant herb.
Let us know in the comments if you have any questions about protecting your plants.
And check out the following articles on gardening in colder weather:
- Lemongrass Winter Care: How to Prepare for the Cold
- How to Grow Parsley in Winter
- The Best Cold Hardy Rosemary Varieties
© Ask the Experts, LLC. ALL RIGHTS RESERVED. See our TOS for more details. Originally published on December 10, 2019. Last updated: January 7, 2020 at 20:47 pm. Uncredited photos: . Originally published December 10, 2019. Last updated: January 7, 2020 at 20:47 pm. With additional writing and editing by Clare Groom and Allison Sidhu.
About Briana Yablonski
Briana Yablonski grew up in Eastern Pennsylvania and currently resides in Knoxville, Tennessee. She holds a Bachelor of Science degree in plant sciences and has worked on farms in Minnesota, Pennsylvania, Virginia, and Tennessee. Now, she spends many hours planting seeds and moving compost at her market garden. When she’s not immersed in the world of gardening, Briana enjoys walking dogs at the local shelter and riding her bike. She believes that gardening fosters curiosity, continuous learning, and wonder.
Suggestions for Keeping Rosemary Alive Over the Winter
This piece was originally published in the Rochester Democrat and Chronicle in November of 2004, and was referenced January 3, 2015, in my column about holiday plants. A number of readers emailed asking for a copy, so I thought I would post it here for your reading convenience. Thanks! — Jane
Q: Any suggestions on keeping rosemary over the winter? I know this is the $64,000 question.
—A.W., via e-mail
A: You’ve come to the right place. As someone who has killed numerous rosemary plants over numerous winters, I can certainly tell you what not to do.
Don’t overwater. Like many plants with strongly-scented, silver-tinged leaves, rosemary prefers dry soil. It’s better to keep it in an unglazed clay pot than in plastic or any material that will lessen the soil’s ability to release moisture. Drainage holes are a must.
Don’t underwater. Many houseplants will tolerate being dry to the point where the leaves wilt. Water them, they perk up, and life goes on. (This isn’t great for the plants, but unless they’re abused this way with regularity, it doesn’t kill them.) Not so with rosemary. After just one time of being seriously dried out, it simply won’t revive. This trait is made more troublesome by the fact that it’s difficult to just look at the plant and tell if it needs water. (Many houseplants’ leaves start to take on a subtle translucent cast, or even just look “sad,” when thirsty. By the time rosemary looks sad it’s already dead.)
Unless you have a cold frame, don’t attempt to leave it outside. Some varieties of rosemary, ‘Arp’ and ‘Madeline Hill’ being two, are hardier than others, but that doesn’t mean they’ll survive an upstate New York winter. I’ve planted both in spots with good winter protection and lost both. The closer you live to the lake the better your chances, but there are no guarantees.
Don’t grow it in the bathroom. Or near the fireplace. High humidity promotes powdery mildew, which shows up as a white, fuzzy coating on the leaves. (Rosemary is, after all, a culinary herb, and powdery mildew doesn’t taste very good, aside from being unhealthy for the plant.) If you must grow rosemary in super-high humidity, at least point a fan at it for a few hours each day to increase air circulation. Confusingly, the plant itself enjoys humidity, so if your house is very dry, consider placing the pot on a tray of pebbles that you can keep wet, while allowing the soil to remain dry.
Give up yet? Don’t do that either. Plenty of green thumbs manage to enjoy rosemary year-round. Here are some of their tips.
Keep in a cool, sunny spot. Rosemary needs all the light it can get and thrives in night temperatures into the low 50s. A cool greenhouse, sunroom, or sunny attic window is ideal.
Watch for the tiny webbing of spider mites. These pests may not have bothered your rosemary outdoors, but may become problematic once inside, where they are encouraged by high heat, low humidity and an absence of predators.
Image courtesy flickr: tdlucas5000
The Essence of Rosemary: Help Rosemary Survive Winter
Rosemary bushes grow to 7 feet tall and wide in mild winter climates from South Carolina to Southern California, but if you live where winter temperatures often dip into the single digits, you will need to keep your plants indoors through the cold months.
Many gardeners grow rosemary in pots year-round, which makes it easy to move the plants inside come fall. But rosemary plants gain more size from year to year if allowed to root freely in well-drained garden soil from spring to fall. Learn to lift and transplant varieties that interest you, especially the trailing ones, which often are best in their second and third years.
For healthy, long-lived rosemary, follow these five simple steps.
1. Lift plants early. Whether you let your plants grow freely in the summer garden or keep them in pots sunk into the soil, lift them in late summer. (Labor Day is a good target date.) For the next six weeks, keep the potted plants in a sheltered spot that receives part-day shade. This will allow them to acclimate to the reduced light indoors.
2. Prune hard. As you lift plants, prune them back by about half their size. Pruned stems are great for drying.
3. Double up on drainage. Rosemary needs fairly dry soil during its winter rest. When potting rosemary for winter, line the bottom of pots with 1½ to 2 inches of fine gravel or perlite and use a fast-draining soil mix. Place pots on a saucer or tray, then water plants from the bottom by filling the saucer with water.
4. Find cool sun. Finding a 50- to 60-degree location close to a south- or west-facing window in your home could be difficult, but this is exactly what rosemary wants. Use florescent lights if none of your windows receive bright sun; for rosemary, light is much more important than temperature.
5. Use a fan. Lack of moving air encourages powdery mildew. To avoid this common problem, ventilate plants with a small electric fan. If you see rosemary leaves going white with mildew, promptly snip out the affected areas, then spray the stricken plant with a mixture of 2 tablespoons milk per cup of water. It works!
Contributing editor Barbara Pleasant, author of The Whole Herb (Square One, 2004), writes and gardens at her home in Virginia.
For the main article, The Essence of Rosemary, .
Container-grown rosemary can be overwintered indoors when given the right conditions. (Photo by )
Overwintering rosemary indoors can be a challenge, but there are ways to turn the challenge into an opportunity so you can enjoy this Mediterranean herb year-round.
Start with a potted rosemary; uprooting and moving an in-ground plant is difficult. If you don’t have any container-grown rosemary, buy one near the end of summer to overwinter indoors.
Rosemary resents being potbound, so if roots are escaping through the pot’s drainage holes by late summer, transplant it into a slightly larger container, using a lightweight potting mix. A few weeks before bringing the plant indoors, move it from full sun to part shade to allow it to adjust to lower light levels.
Make the final move indoors before the first frost. Situate your rosemary in a cool, well-lit room or enclosed porch; ideally, the temperature should stay between 10° and 15°C. A spot that’s too warm can stress the plant and attract whiteflies or spider mites. If that happens, apply insecticidal soap.
Rosemary appreciates lots of light and may get leggy without it. A southern or southwestern exposure is best, or set the plant under a fluorescent light on a timer.
Good air circulation helps prevent powdery mildew. Don’t crowd the plant and keep it away from humid locations. A small fan blowing on the herb for a few hours a day increases air circulation. Treat powdery mildew by removing infected leaves and spraying the plant with a mixture of baking soda and water.
Rosemary is classed as drought tolerant and thrives in lean, well-drained soil. However, this is one herb that doesn’t like completely dry conditions. In winter, water when the top of the soil is dry. In spring, as growth begins, keep the top of the soil slightly moist, but not drenched or waterlogged.
There’s no need to fertilize through the dark winter months, but begin feeding every other week in early spring with a balanced formula, such as 20-20-20.
Once outdoor temperatures rise to about 12°C, acclimatize the potted rosemary by setting it outside in part shade for the day and bringing it indoors at night. As soon as all danger of frost has passed, the plant can stay outdoors for the summer, ideally in your hottest, sunniest garden spot.
More about rosemary on Garden Making
- How to treat powdery mildew on rosemary?
VIEW ALL HERBS
(Rosmarinus officinalis) – Half-hardy Perennial
“There’s rosemary, that’s for remembrance.” A classic Shakespearean line and one that reflects rosemary’s true character. As far as can be told, the tradition of rosemary for remembrance stems from the Greeks, when students wore garlands of the herb in hopes of passing their final exams. Since then, it has been a symbol to remind many generations of faith in love, loyalty in friendship and honor for the dead. It is has been used to help meats and wine to “remember” their flavor and helping stomachs to “remember” their appetites. It was also known in the 16th century as an herb that only grew well in homes where the women of the house were in charge.
This evergreen shrub from the Mediterranean contains antioxidants which slow the aging process, a big part of which is remembrance – and perhaps where it inherited its reputation. Rosemary has a heavy, recognizable flavor that combines those of pine, mint and ginger. It has bluish-green leaves that resemble needles and can grow to 6 feet tall! Soft lilac or bright blue two-lipped flowers bloom in late spring to mid-summer.
Rosemary is a garden favorite but can sometimes suffer during the long Southern winters. With a little work, however, your rosemary will live to see the mild winters it thrives in. To help rosemary through the extremes of the summer and winter, mulch well. It also helps to prune dead areas in the spring time to help foliage to come back full. Also, adding egg shells to the water occasionally helps to keep rosemary in top shape.
Kitchen Gardens grows and recommends the following varieties of basil – we think you’ll enjoy them, too!
Creeping Rosemary (R. officinalis ‘Prostratus’ )
Grows only 6 to 12 inches tall, but can spread to 3 feet
Produces lavender flowers