Rosemary, the International Herb Association’s Herb of the Year for 2000.
Throughout its long and varied folk history, rosemary (Rosmarinus officinalis) has been esteemed as a token of love, loyalty, and friendship. In Italy, women would tap a sprig of flowering rosemary against the fingers of a would-be lover for any signs of reciprocal affection. Italians also tossed rosemary sprigs into the grave as a symbolic gesture to remember and celebrate the life of the deceased. And in the Victorian England’s “language of flowers,” rosemary signified “remembrance.” According to European folklore, rosemary could ward off evil and grew only in the gardens of the righteous. Greek scholars placed rosemary wreaths on their heads to stimulate their brains and aid memory before taking exams. (Today, studies are under way on rosemary’s antioxidant properties and their effect on the brain.) Rosemary incense was burned to fumigate courtrooms in seventeenth- century France and England, and during World War II, French hospital officials, desperate for supplies, burned rosemary and juniper branches for the same purpose.
I received my first rosemary plant as a gift from a dear friend along with an old adage: “Where Rosemary flourishes, the Lady dominates.” I often find myself quoting this at plant sales; women shoppers laugh knowingly and purchase a plant. A version from eighteenth-century Gloucestershire is blunter: “Rosemary will not grow well unless the Mistress is master.” (It’s said that some men were so outraged by this statement that they ripped out any robust rosemary plants that they encountered.) At our house and nursery, more than forty different cultivars of rosemary now flourish, a circumstance my wife constantly points out to me.
“Rosemary is to the spirit as lavender is to the soul,” another old saying goes, and I do feel a gardening “spirit” as I walk among my rosemary cultivars. Of all the herbs I grow, rosemary blooms in the bleakest of times: an Oregon winter. As I brush against the foliage, its fragrance—reminiscent of pine forests with a hint of ginger—is always uplifting and refreshing. In the garden, rosemary always looks good and needs little care.
Rosemary is an evergreen shrub of the mint family (Lamiaceae). It has inch-long dark green, leathery, needlelike leaves whose edges roll down and inward. The undersides are covered with a silver fuzz. Small clusters of 1/2-inch flowers on short stalks grow in the leaf axils on the previous year’s woody growth during the fall and winter. The two-lipped corolla resembles a miniature orchid: the upper lip is narrow and two-lobed; the lower lip has two narrow lateral lobes and a much larger, ruffle-edged central lobe. The flowers of most cultivars are blue, anything from pale blue to rich, fluorescent dark blue, but forms with white, pink, and even red flowers also exist. All are extremely attractive to honeybees. The fruit is a tiny, smooth, round nutlet.
Rosemaries may be either upright or creeping. During their first three years of life, upright forms grow straight upward and remain narrow, but later they bush out. Despite the saying that rosemary cannot grow taller than 6 feet (the height of Jesus Christ) in thirty-three years (his life span), an ancient rosemary I saw growing in the bottom of a dry moat in England is some 10 feet tall and 12 feet wide.
The creeping forms have twisting, swirling branches that make them excellent candidates for bonsai or containers. Planting one in a hanging basket places branch tips right at your fingertips where they’re handy to snip for use in cooking. In Southern California, creeping rosemaries make great ground covers, filling entire banks and spilling over retaining walls to great effect. They also tend to root as they spread, thus preventing soil erosion. The leaves of most of the creepers are about a half inch shorter than those of the uprights and much glossier.
Rosemary is native to the dry, rocky hillsides of the western Mediterannean and North African coastlines (the generic name, Rosmarinus, is Latin for “dew of the sea”). It is quite tolerant of salt spray.
A drought-tolerant sun lover, rosemary does well in sandy or chalky soil. Its shallow, fibrous root system needs good drainage and can succumb to root rot if overwatered. Recent rainy winters here in Oregon have damaged my stock rosemary plants, so I am amending my clay soil with copious amounts of organic matter to increase aeration and replanting the rosemaries in hilled rows to improve drainage further. Although its optimum soil pH is 6.8, rosemary will tolerate a range from 5 to 8.
Rosemary is generally hardy to 15° to 20°F (USDA Zone 8, 7 with protection) and should be planted in the warmest, driest part of the garden, out of the winds, which can dehydrate leaf tips.
Upright rosemaries are much hardier than prostrate forms, but some are hardier than others, particularly ‘Arp’ (hardy to 10°F with protection), ‘Hill Hardy’, ‘Salem’, ‘Benenden Blue’, ‘Alba’, ‘T.S.’, ‘White Flowered’, ‘Golden Rain’ (‘Joyce DeBaggio’), and ‘Herb Cottage’. I rarely get creeping rosemaries to overwinter, but a 2-foot-tall semiprostrate ‘Severn Sea’ planted in an alleyway between a shade house and a greenhouse has survived for ten years and withstood temperatures as low as 3°F for one week with no snow cover. Other creepers rapidly succumb to our winter wet, probably because moisture trapped in their foliage predisposes them to fungal diseases. Where winters are harsh, both forms of rosemary overwinter well in a cool greenhouse.
Indoors, place rosemary in a well-lit window or under fluorescent lights and water sparingly but never let the soil dry out. Instead of misting the foliage, place the pot on a moist gravel bed if the air is extremely dry.
Too large a pot may keep the soil too moist, producing the same effect as overwatering. Brown leaf tips indoors may be a sign of overwatering. Avoid adding fertilizer until late winter, when new growth begins and the day length has increased enough to enable plants to utilize the added nutrients.
I winter many of my rosemary stock plants in an unheated greenhouse. Ventilation is a must even in the dead of winter. When I had a few weeks of cold weather a few years ago and couldn’t open the windows, the narrow-leaved cultivars ‘Blue Boy’, ‘Mozart’, ‘Benenden Blue’, and ‘Majorca Pink’ all came down with powdery mildew. I have never seen it on the broad-leaved cultivars, such as ‘Tuscan Blue’ or ‘Gorizia’, however.
Aphids, scale insects, or mealybugs may sample an indoor rosemary, but in my greenhouse, I find that other herbs, such as basils, sweet bays, or lime trees, tend to attract them elsewhere.
My “ideal” rosemary has forest green, rather broad leaves like those of ‘Tuscan Blue’ or ‘Herb Cottage’. ‘Arp’ leaves are too grayish, and the plant is much too branchy and bare for my taste. Give me a dense, formidable plant such as ‘Gorizia’, an Italian import that is not as winter-hardy as ‘Arp’.
I also like Tom DeBaggio’s introduction ‘Golden Rain’ (‘Joyce DeBaggio’), a unique upright cultivar with a dark green vein running down the center of each narrow gold leaf. In the heat of summer, it looks more like a golden juniper than a rosemary, but in late winter, it produces a host of dark blue flowers, much like those of ‘Benenden Blue’.
Among the creeping rosemaries, which generally bloom from Thanksgiving through early spring, ‘Wood’, ‘Kent Taylor’, and ‘Mozart’ have flowers of the brightest blue. Later in spring, I sell many pots of ‘Shimmering Stars’ and ‘Dancing Waters’ as each of these creeping forms has great arching branches covered in bloom at that time.
Potted rosemaries lend themselves to topiaries (see Sally Gallo’s Herb Topiaries, published by Interweave Press in 1992), either standards (miniature trees or lollipop-shaped plants) or plants trained to wire frames in the shape of circles and hearts. ‘Miss Jessopp’s Upright’, ‘Blue Spires’, and ‘Arp’ are especially suited for the former; ‘Santa Barbara’ (‘Lockwood de Forest’), ‘Collingwood Ingram’, ‘Prostratus’, and ‘Majorca Pink’, for the latter.
‘Santa Barbara’ (‘Lockwood de Forest’), with robin’s-egg blue flowers, makes a terrific bonsai specimen with relatively little work. Just plant in a container and selectively prune out some of the smaller, finer branches and presto! a faux bonsai in less than a year.
Rosemary collectors will want to keep an eye out for three relatively recent introductions. ‘Portugese Pink’ has nice pink flowers and finer foliage than ‘Majorca Pink’. Another cultivar from Portugal, as yet unnamed, has small but intense ruby-colored flowers. I grow mine in a pot, but my cousin in Bolinas, California, says it makes an admirable 2- to 3-foot-tall, finely textured shrub.
Finding the third of these cultivars, ‘Silver Spires’, was like searching for the Holy Grail. The sixteenth-century English herbalist John Gerard wrote of a variety with white variegation, but this had been lost until about five years ago when a similarly marked sport appeared in an English nursery. Its descendants aren’t widely available in the United States yet. I have a plant that a friend brought from England, and it is a very slow grower. Few visitors recognize it as a rosemary because its leaves have silver margins. Its foliage tends to revert back to solid green, and I haven’t been able to propagate it yet. It’s not a plant I’d recommend you acquire unless you like coddling plants as a hobby.
Rosemary seeds may take as long as a year to germinate, and even then, only about 30 percent of the seedlings survive except under warm conditions. (However, the few volunteer seedlings that have come from my R. officinalis plants look quite vigorous; in fact, the ancestor of the most winter-hardy of rosemary cultivars, ‘Arp’, was a chance seedling that withstood severe temperatures in Arp, Texas.)
Because rosemary cultivars don’t come true from seed, I propagate them from stem cuttings. The technique is easy, quick, and generally effective. From late September through November, I look for new growth that is just turning from green to reddish brown and take 4- to 6-inch cuttings with a sharp knife or clippers. I pinch 1/4 inch off each tip to promote branching. Next, I carefully remove each leaf from the lower third of the stem. It is a tedious job, and my fingers turn sticky and brown from the resin in the leaves, but fewer cuttings die because the living cambium layer of the stem is better preserved, minimizing the opportunity for disease to enter.
I dip each stem in a rooting hormone and then stick it in a sterile medium consisting of equal parts peat moss, perlite, and vermiculite. I have also used pure perlite or coarse sand with good results. Heating the soil to at least 10° warmer than the air temperature (ideally, 68° to 72°F) greatly facilitates rooting. In the old days, fresh horse manure provided the heat; today I use either an electrical mat or hot-water pipes. If a cutting hasn’t started to root within a month (tug on it gently; if it comes right out, it hasn’t) or turns brown, it’s not going to make it. I transplant the rooted cuttings into 4-inch pots, and they are ready to sell in four to six weeks.
If you have a rosemary plant, you can harvest it all year long. The flavor is so strong that I use only a small sprig in a batch of spaghetti sauce or in savory dishes such as lamb, pork, hearty stews and soups, and shellfish. You can also throw rosemary sprigs (perhaps the prunings from your bonsai) onto barbecue coals; Mike Hanselman of Blue Heron Herb Nursery in Sauvie’s Island, Oregon, recommends using fresh, straight, thick stems of ‘Tuscan Blue’ as shish kebab spears.
Andy Van Hevelingen resides in Newberg, Oregon, where he and his wife, Melissa, are passionate about growing herbs.