Designing and Maintaining that Seaside Garden...
By Deb Lambert
Approach your seaside gardening armed with basic knowledge of coping with the elements, as well as design concepts, and you'll realize success. While the last discussion dealt with warming effects, wind, sand, and sandy soil, there are several other factors to consider before delving into the subject of suitable plant material.
While salt in very small quantities will actually promote vigorous root systems, larger quantities, such as those deposited on the landscape during severe coastal storms, are toxic to plant tissue. Fortunately, salt has an affinity for water - remember how table salt clogged up the salt shaker during humid weather? Salt accumulates in the soil, since after the moisture evaporates, the salt moves about through the soil. Drenching the soil, on a regular basis, with fresh water will leach salt downward and safely away from root zones. Because salt is attracted to water, gardens and lawns subjected to coastal flooding, should be flushed with fresh water as soon as standing sea water has drained away.
Applications of limestone and gypsum are also helpful in repairing damage after severe storms. Garden gypsum (and lime) neutralizes the acidity associated with sea salt, road salt and dog urine spots on lawns. Gypsum opens up heavy soil, improving drainage, but also binds together loose, sandy soils. And, as mentioned last time, the incorporation of compost and other organic material is invaluable in improving texture and the moisture-holding capacity of sandy soil, and should be added, annually. Consider using polymers, especially around new plantings or in window boxes and container gardens. These crystals absorb and retain incredible amounts of water, acting as a reservoir in fast-draining soils, or in times of drought.
What makes some plants better suited for seaside culture than others? Many develop extremely deep root systems as they seek water. Some plants have facilities, like succulent leaves, for storing moisture, while others have protective leaf surfaces to reduce moisture loss. Plants with smooth, protective surfaces are pines, yews, some hollies, yucca and sea holly. Plants like heather and juniper have foliage comprised of small, overlapping scales which affords salt and wind resistance. Silver-leaved plants are protected by the same tiny hairs which give them their grayish coloration. Salt crystals are caught in the hairs, thus protecting the leaf surface. Glaucous plants, those covered with a whitish "bloom," are afforded similar protection, bayberry leaves being a case in point. Often, the fruits or berries of seashore plants are protected with a hard or waxy coating. Buds, too, are protected with hard, shiny surfaces or tiny hairs.
If that seaside site is new to you, observe which plants flourish naturally, see what plants have proven successful for your neighbors, learn about your various exposures and how storms affect them. If you choose your plants wisely, natural windbreaks will prove more successful than fences or large walls. A mixed planting will be more attractive and vigorous, holding the soil with its roots, while framing or accenting the ocean view. Low brick or stone walls will protect low-growing plants from the wind, creating a warm micro-climate - all this without affecting the overall view.
Plants that will survive in the most exposed areas include rugosa rose, black pine, autumn olive, shadbush, Scotch broom, privet, American beach grass, most species of juniper, several species of white oak and white poplar. Plants needing a bit more shelter are little leaf linden, Norway and red maple, beach cherry and plum, purpleleaf plum, flowering crab, Swiss stone pine, willow species, Austrian and Scotch pine, Colorado blue spruce, honeylocust, black locust, London plane and white mulberry.
Having similar preferences are barberry, burning bush (these first two may be on your local 'invasive species' list, so might be unavailable), Japanese holly, inkberry, spirea, rose of Sharon, shrub roses, hydrangea, viburnum, grape, wisteria, highbush blueberry, potentilla and butterfly bush. Many of the ornamental grasses grow well at the seashore, as do groundcovering plants like bearberry, heather, thyme, St. Johnswort, artemisia, yarrow, herbs and creeping junipers.
This is just a thumbnail sketch of seaside gardens, outlining some of the basics. For more in-depth information and expanded plant lists, consult one of the many fine references available at bookstores or at your local garden center.
©Deb Lambert 2008/All ©2004-2007 photos from the photographer's seaside gardens.