For Drought-Tolerant Plants, Look to the Seashore
Sometimes we can find solutions for problems we face within our gardens by studying what thrives under similar conditions in the wild. If you’re challenged by dry soils at home and your summer plans include visiting the coast, you might spend a few minutes out of the water, observing the plants that persist in the harsh conditions of the coastal ecosystem. Here are a few I've found to be both rugged and garden worthy.
Beach wormwood, or Artemisia stelleriana, looks similar to the familiar dusty miller, but it's hardier and more drought tolerant.
BEACH AND DUNE PLANTS
Plants that grow in the most exposed areas of the seashore must endure harsh sun, drying winds, salt spray and poor soil.
Strictly speaking, beach wormwood (Artemisia stelleriana), is not native to the North American coastline, where it now often resides. This perennial has less conspicuous flowers than many fellow members of the aster family, but it compensates with showy, felted foliage. It forms mounded rosettes that hug the ground. It has an excellent ability to tolerate drought.
Although the false, or wild, indigos (Baptisia) are often associated with locations both farther south and inland, I’ve seen horsefly weed (B. tinctoria) growing in beach sand as far north as Massachusetts’s Cape Cod, where it is a native. One of the more compact baptisias, it grows densely in dry, sunny conditions. Small bright yellow flowers cover it in midsummer.
Liatris scariosa, or northern blazing star, grows in dry open areas, such as along the upper edges of cobble beaches and brackish marshes in much of coastal New England and New York. This two-to four-foot plant offers spectacular blooms that can consist of as many as eighty individual pink-purple flowers.
Most people associate cacti with the Southwest, but eastern prickly pear (Opuntia humifusa) grows as far north as Cape Cod. Opuntias grow into upright plants as high as sixteen inches or form flat mats as wide as three feet. The thick, flattened pads store water, letting the plant thrive in extremely dry conditions. Eastern prickly pear’s three-inch bright yellow flowers appear in late spring.
Seaside goldenrod (Solidago sempervirens var. sempervirens) is one of the showiest of coastal plants. It can be found from Newfoundland to Virginia; it also thrives farther inland alongside salted highways. It grows as happily on the edges of salt marshes and sand dunes as it does in peaty or sandy soils in close proximity to salt water. In exposed locations, plants sprawl in prostrate mats; when growing in combination with other species, they adopt a more erect form and can reach a height of six feet.
PLANTS OF THE COASTAL PLAIN
In the coastal plain, a landscape more sheltered than beaches and dunes, highly specialized plants arrange themselves in beautiful combinations with lichens and moss, forming jewel-box gardens that are truly low maintenance.
Bear berry follows its dainty flowers with bright red fruit.
Often growing under pitch pine and bear oak, bearberry (Arctostaphylos uva-ursi) is a common ground-covering subshrub of typical sand plain communities. It forms trailing mats of leathery small leaves and offers pale pink to white flowers in late spring. Some forms also bloom in the fall, often showing more richly colored flowers in that season.
Sweet fern (Comptonia peregrinum) is a twiggy shrub that grows on dry roadsides and woodland clearings inland and along the coast. It loves sun and quickly disappears in shade. Its fernlike leaves, which are distinctively fragrant when crushed, make it easy to recognize.
Beach plum (Prunus maritima) grows happily in dunes and sandy soils from New Brunswick to Delaware and Maryland.
Bear oak (Quercus ilicifolia) is another plant of variable size and habit. It can be found on dry, rocky, and sandy soils on the northern coastal plain from southern Maine to New York, as well as farther inland. Forming a shrub or small tree, rarely exceeding fifteen feet, bear oak has an abundance of attractive leaves that are generally under five inches long and nearly as wide. The species name ilicifolia refers to the leaves’ resemblance to holly (Ilex) foliage.
Arrowwood (Viburnum dentatum) grows from southeastern Massachusetts and Rhode Island south to New Jersey. It prefers moist to dry sandy soils in sunny areas or borders of thickets within sight of, or adjacent to, salt water. It has a rounded form and grows between three and eight feet tall. Large, coarsely toothed shiny leaves are its main draw, and its smooth gray bark makes it an interesting garden plant in and out of the beach-going season.
For ideas from the West Coast, see this post on tough plants that thrive on Alcatraz.
Image credits: Artemisia by Patrick Standish/CC BY 2.0; Arctostaphylos by Krzysztof Ziarnek, Kenraiz - Own work, CC BY-SA 4.0
