Denizens of the Drylands

Whether your garden spot boasts sandy or gravelly soil that drains too quickly or reflected heat from a concrete walk, ­driveway, or foundation wall, it’s an ideal position for a whole host of xeric herbs.

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Many sun-worshiping herbs find the dryland garden ideal because they originated in some of the world’s harshest environments. Sun, heat, and quick drainage help these plants thrive.

Photograph by Rob Proctor

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Those of us who garden in the arid west likely have more than a passing acquaintance with dryland herbs. Any water-conserving landscape plan worth its salt contains a sampling of culinary favorites such as rosemary, sage, thyme, and lavender. The capacity to withstand dry conditions is a real attribute in dry climates, where water for irrigation may be costly and limited or simply unavailable.

Whether your garden spot boasts sandy or gravelly soil that drains too quickly or reflected heat from a concrete walk, ­driveway, or foundation wall, it’s an ideal position for a whole host of xeric herbs.

Westerners aren’t the only ones who have a place in their gardens for xeric (low-water) herbs, however. Regardless of how generously nature provides rainfall where you live, some part of your property is inevitably too dry for most plants to survive without supplemental irrigation. There’s that stretch of the Sahara running along the front sidewalk, the bit of the Gobi on top of a stone wall. The soil south of the garage under an overhanging eave is so dry it resembles the Mojave in Massachusetts or the Sonoran in South Carolina.

Nurturing dryland herbs

Fortunately, hundreds of herbs not only tolerate but prefer dry conditions. In fact, constant moisture spells certain death to plants that hail from some of the world’s harshest regions. Whether your garden spot boasts sandy or ­gravelly soil that drains too quickly or ­reflected heat from a concrete walk, driveway, or foundation wall, it’s an ideal position for a whole host of xeric herbs. No sacrifice is required, either, because these are some of the most aromatic and elegant plants in all herbdom.

Most dryland herbs are sun worshipers, requiring as many hours of uninterrupted sunshine as your climate can deliver. Equally essential is quick drainage. If you live where the annual rainfall is more than 15 inches, you have no choice but to remedy poor drainage or risk fatal rot. Choosing a sloping site to speed runoff is one option; installing drainpipes to carry off water beneath the surface is another. In hot, humid climates, it might be best to plant dryland herbs in raised beds containing 6 to 12 inches of coarse builder’s sand.

In more moderate climates and in sites where drainage is already fairly good, several inches of coarse sand or fine gravel mixed into the existing soil will create the mineral-rich, humus-poor soil favored by drought-loving herbs.

How much supplemental irrigation your established beds of dryland herbs will need depends on the amount of natural rainfall and the rate of evaporation, among other factors. On the other hand, if I forget to provide small transplants with a regular drink, they turn to toast before the first week is out. Once the plants have taken hold, water as necessary to keep plants compact and slow growing but alive and healthy.

Choosing dryland herbs

Sage was my first herbal love; I remember begging my mom to add more to her meat loaf and turkey stuffing. If you grew up during the herb-impoverished 1950s, sage was probably your introduction to the world of herbs, too. Though garden sage (Salvia officinalis) remains indispensable in the kitchen, its soft gray-green foliage is highly ornamental in the dry garden. My favorite cultivar, ‘Berggarten’, has substantial oval leaves with a distinctive rickrack edging. For a more lively palette, try ‘Tricolor’, with leaves splashed with cream, pink, green, and purple; ‘Icterina’, variegated green and gold; or sedate ‘Purpurascens’, with grayish green leaves lightly brushed with purple.

Pineapple sage (S. elegans) offers flamboyant scarlet flowers in fall and the sweet scent and flavor of pineapple. Gardeners in cold regions can grow this tender perennial in a pot and bring it indoors when frost threatens.

Some of the showiest plants for dryland gardens are the ornamental sages. The biennial silver sage (S. argentea) forms cabbage-sized woolly-leaved rosettes in its first year and puts up white flower spikes in its second. Species with smaller silvery leaves and discreet white flowers include compact S. candidissima and S. frigida. S. cyanescens has felted gray foliage and the violet-blue blossoms that are more typical of the family. Blue-flowered desert sage (S. dorrii), native to many of the western states, is the most drought tolerant of all the silver sages, calling even Death Valley home.

Two tender shrub sages are deservedly popular in regions with mild winters. The leaves of California native purple sage (S. leucophylla) turn nearly white in midsummer, contrasting dramatically with its pale purple flowers. Hummingbirds flock to red-flowered cherry sage (S. microphylla). Good cultivars include ‘Rosita’ (candy pink), ‘San Carlos Festival’ (magenta), and ‘Oxford’ (crimson).

More flavors and fragrances

The thymes are another large genus of culinary and ornamental herbs that prefer dry soil. Ground-hugging woolly thymes (Thymus praecox subsp. arcticus ‘Lanuginosus’ and T. neiceffii) are handsome trailing down a wall or a boulder or creeping between stepping stones. Other thymes include lemon thyme (T. ¥citriodorus), mother-of-thyme (T. pulegioides), and common thyme (T. vulgaris). So bewildering is the variety of leaf and flower color, fragrance, flavor, and growth habit, compounded by a confusion of names in the nursery trade, that it’s better to buy what you like rather than relying on a label. Bruise a leaf to determine which kinds would best enhance a pot of stew or a roast chicken (see also “The Best of Thymes,” by Harriet Flannery Phillips, in the April/May 1991 Herb Companion).

Frost tender, but easily grown inside in a sunny window during the winter, rosemary (Rosmarinus officinalis) is an evergreen, strongly aromatic shrub universally loved for both landscape and culinary punch. The blue-flowered cultivars ‘Lockwood de Forest’ and ‘Prostratus’ have a trailing habit ideal for spilling down a wall or over the side of a large container. ‘Majorca Pink’, ‘Pinkie’, and ‘Roseus’ sport pink flowers. ‘Aureus’ has variegated yellow foliage.

With saffron worth more than its weight in gold, frugal gourmets may wish to start a patch and harvest their own. Saffron crocus (Crocus sativus) blooms in late summer. Don’t pick the flowers; simply snip out and save the reddish-orange stigmas. One warning: It takes 60,000 flowers to yield a single pound of seasoning. If you’re thinking big, get busy planting.

One fall, I accidentally spilled seeds of red orach (Atriplex hortensis var. rubra) on the driveway. The following spring, each and every one happily germinated along every crack in the concrete. Any plant this obliging is bound to be a bit of a pest in the garden. Grow red orach only if you aren’t annoyed at the prospect of having to pull hundreds of misplaced seedlings. For me, the delicious spinachlike leaves and the striking wine-red color make this pest worth the bother.

Another intrepid but more tractable vegetable for the dry herb garden is sea kale (Crambe maritima). Its silver ruffled leaves are as tasty as they are pretty, and the edible white flowers make a pretty garnish for coleslaw.

One fall, I accidentally spilled seeds of red orach (Atriplex hortensis var. rubra) on the driveway. The following spring, each and every one happily germinated along every crack in the concrete. Any plant this obliging is bound to be a bit of a pest in the garden. Grow red orach only if you aren’t annoyed at the prospect of having to pull hundreds of misplaced seedlings. For me, the delicious spinachlike leaves and the striking wine-red color make this pest worth the bother.

Flowers for the kitchen

Many flowers of culinary herbs are quite scrumptious, but don’t limit yourself to these—dry gardens can host a number of flowers grown for their edible blossoms alone. If you do constant battle with a plague of grape hyacinth (Muscari armeniacum), the most satisfying revenge is to eat them. Their purple flowers look and taste like diminutive clusters of grapes and give an unexpected zing to salad greens.

Clove and cottage pinks (Dianthus caryophyllus and D. plumarius) lend a touch of spicy clove or jasmine to salads and desserts. Calendula daisies (Ca­lendula officinalis) have a slightly peppery taste. The flowers of Johnny-jump-up (Viola tricolor) are mild in flavor, but their pretty faces promise to brighten an afternoon tea whether floating on a punch or adorning a cucumber sandwich.

Designing with xeric herbs

From a design standpoint, the biggest challenge to pulling off an intriguing and dynamic garden using xeric herbs is their tendency to look alike. Small, grayish leaves and scrubby habit are the norm since these traits help the plants cope with the drying winds and searing heat of their native habitat. A garden that entertains and stimulates the eye needs variety and strong contrasts of color, texture, form, and size. To get these effects, you must seek out the nonconformists among the xeric herbs. Particularly valuable are those with oversized foliage, dramatic silhouettes, and unusual coloring.

No group of plants is more architectural than the yuccas, whose tight rosettes of swordlike leaves have inspired such common names as Spanish bayonet, dagger plant, and Adam’s needle. A large number of variegated cultivars are available and even more spectacular than the plain green forms.

Armed with spikes and prickles, the sea hollies look like some sort of particularly nasty medieval weapon. The foliage of Eryngium bourgatii is heavily cut and spined with silver veining. E. planum ‘Blaukappe’ sports thistlelike, metallic blue flowers that keep their color well for many weeks, even in strong sunlight.

If you can’t resist fuzzy, silvery foliage, you must have the biennial Turkish mullein (Verbascum bombyciferum). Compared to lamb’s-ears, these leaves could have come from Paul Bunyan–sized sheep. The woolly rosettes send up lax candelabras of cool yellow flowers in their second season. Inula verbascifolia and shaggy hawkweed (Hieracium villosum) provide more modest silvery and furry foliage, the latter as long-haired and soft as Angora bunnies. Both send up yellow dandelion-style daisies.

For a lacy effect, there’s rue (Ruta graveolens), with silvery blue filigreed foliage, and horned poppy (Glaucium flavum), with blue, deeply ruffled leaves and showy golden flowers. Artemisias bring the magic of hoarfrost to the summer garden, their intricately cut foliage creating a handsome foil to more solid forms. Artemisia ‘Powis Castle’, A. canescens, A. ludoviciana ‘Silver King’, beach wormwood (A. stelleriana), wormwood (A. absinthium), and southernwood (A. abrotanum) all bear exceptionally ­attractive foliage. Tanacetum cinerariifolium, a cousin of the medicinal herb feverfew (T. parthenium), offers elegantly cut grayish leaves and white daisies, while Anthemis marschalliana sports clear yellow daisies above finely dissected silvery doilies of foliage.

Just plain pretty are silver-leaved horehound (Marrubium rotundifolium) and Himalayan mint (Mentha longifolia subsp. himalayensis). Like all other mints, this one runs; for sanity’s sake, plant it in a 5-gallon bucket with the bottom removed.

As a rule, herb flowers are quiet and unobtrusive, so look for those with unusually bold and extravagant blossoms to help the herb garden break out of its prim and proper demeanor. Take the drop-dead-gorgeous agastaches. Sunset hyssop (Agastache rupestris), aptly named for its rose-tinted orange flower spikes, incidentally smells exactly like draft root beer. Pink-flowered A. pallida subsp. pallida and hummingbird mint (A. cana) both carry a fresh minty fragrance.

Although purple coneflower (Echinacea purpurea) often appears on Xeriscape lists, it is much heartier when watered during dry spells. Its relatives E. angustifolia and E. pallida are the ones that can handle drought with aplomb. All offer bright pink daisies with raised central cones, orange in the first two, a vivid burgundy in the third.

The flowers of High Plains desert natives four-o’clock (Mirabilis multiflora) and winecup (Callirhoe involucrata) are unabashedly magenta, a color that is especially engaging when played off against the soft pink spikes of shell-leaf penstemon (Penstemon grandiflorus). Whatever their flower color, the dozens of western penstemons are always a solid choice for the dryland garden.

Many of the mallows are real water guzzlers, but some of their cousins put up with the dry life. Stately tree mallow (Lavatera thuringiaca), a shrub-sized perennial that dies back to the ground in winter in cold climates, is fairly smothered with bright pink blossoms for most of the summer. Burgundy, soft pink, and white-flowered dwarf and variegated-leaved forms are available. ‘Barnsley’ is one of the best, its pale pink flowers handsomely marked with a dark pink center eye. Pink-flowered checkerbloom (Sidalcea malviflora) and hollyhock mallow (Malva alcea var. fastigiata) also tolerate drought.

Lion’s-ear (Leonotis leonurus), a hardy shrub in mild-winter areas, may be grown as an annual in colder regions. The orange blossoms, borne shish kebab fashion along tall spikes, fairly glow when paired with brilliant purple statice (Limonium gmelinii).

This is just a taste of some of the best of the multitude of dryland herbs. These tough and resolute characters can transform your personal patch of desert real estate into a garden that supplies not only a feast for the eye, but for your other senses as well.

Marcia Tatroe writes a gardening column for The Denver Post. Her several books, including Perennials for Dummies, have inspired beginning and experienced gardeners alike. She lives in Aurora, Colorado.