The Green Scene column in the July 31 Real Estate section incorrectly described the pH scale of acidity or alkalinity. The scale runs from 0 to 14, with 7 neutral, less than 7 acidic and greater than 7 basic. (Published 8/3/04)
Salt water, sand and sunny breezes -- the qualities that make the beach such a wonderful place to visit or to live -- are the same elements that make gardening there such a challenge.
But it's only challenging, not impossible. If you look around, you can find lots of examples of beautiful gardens in your shore community. In fact, that's the best place to start when you're looking for ideas for planting near the ocean -- at your neighbors' yards and in municipal plantings.
The neighbors who have great gardens have already gone through some of the trial and error it takes to establish what will and will not flourish in a seaside setting. Local plantings will have been designed for maximum visual impact with plants that survive without need for extraordinary horticultural practices. You can get a lot of information by just walking, biking or driving around. Talk to as many people as you can. Most gardeners are eager to share stories and provide advice.
Whether you live at the beach full time, or only visit on weekends, an attractive garden is a good investment. Not only does it enhance your own enjoyment of the scene, but it also can provide privacy and add to the property's value.
Most parts of the East Coast, except for southern Florida and northern New England, fall into Zones 6 to 8, as reflected by the Agriculture Department's Hardiness Zone Map, which divides the country into sections depending on the low temperatures typically reached during winter. Plants in Zone 6 need to withstand temperatures as low as 10 degrees below zero; in Zone 8, the average minimum temperature is 10 to 20 degrees. Within every zone, however, are microclimates, where local conditions are more exposed or more protected. Sometimes a hedge or fence can create more protected conditions in a yard.
Of course, beach plants need to withstand more than possible cold temperatures. They must thrive in sandy soil, be tolerant of salt, in the ground and in the air, and be able to withstand strong winds. Prevailing sea breezes can cause trees to bend, giving them the appearance of a bonsai.
Though these conditions limit the number of plants that do well at the beach, there are still plenty to choose from. Japanese black pine, for example, already grows with a wind-blown, bonsai-like habit, meets the criteria for thriving in the nutritionally poor sand and tolerates salty conditions.
There are other plants that don't mind a little salt. A range of 1,000 to 2,000 parts per million in soil is moderately tolerated by a surprisingly wide range of plants. Some research contends that certain salt sprays discourage fungus and insects. Liquid Copper 4E, manufactured by Extremely Green Gardening Co., for example, is a special formulation of copper salts for control of fungal diseases of vegetable, fruit and ornamental crops.
As is true of any kind of gardening, the first thing you need to do is find out what kind of soil you have, acid or alkaline. This is measured by pH, a measure of the acidity or alkalinity on a scale from 0 to 14, where 7 is neutral, greater than 7 acidic and less than 7 basic.
Conifers and some shrubs, such as azaleas and hollies, prefer acidic soil, while many vegetables and shrubs, such as lilacs and boxwoods, prefer slightly more alkaline conditions. You can buy kits for testing soil at garden centers, or you can contact your county or municipal Cooperative Extension Service. Find them under county listings in the phone book or online.
Almost all soils benefit from supplements. Peat moss, composted manure, garden clippings and homemade compost can improve nutrients and water-retention capability in sandy soil. Some shore dwellers collect natural compost, such as objects that wash up on the beach including seaweed, dead fish and crab shells. Mulching with composted materials, from two to four inches, also helps retain moisture in sandy soil and windy conditions. It can be tilled into the soil. The best thing you can do for your seaside garden is to improve the soil as much as possible before you start planting.
Besides "sculpting" trees, wind can slow growth rates and cause plants to need more moisture. Some gardeners advise starting small with beach plantings, because that generally allows plants to become more established before they get tall enough to face the wind. (They're also less expensive than larger specimens.) New trees might need to be staked for as long as two years -- a year longer than inland plantings.
If your property is not protected from the wind and salt spray, you may want to use a combination of fences and hedges to shield inner plantings. Fences and hedges also provide privacy, through they may impede views.
When it comes to choosing plants, seashore conditions make a superb case for going native. It's hard to go wrong with native plants, as they are already adapted to local conditions. Grasses, such as American beach grass (Ammophila breviligulata), sea oats (Uniola paniculata), switch grass (Panicum virgatum) and little bluestem (Schizachyrium scoparium), as well as grassy-looking plants that aren't related to true grasses, such as blue-eyed grass (Sisyrinchium), about 90 species in the iris family, and sea lavender (Limonium bellidifolium), are excellent choices.
Other low plants are heath, heather and, with some shade, leucothoe, a member of the heath family.
For shrubs, try crape myrtle, with beautiful flowers and interesting bark; pussy willow; beach plum (Prunus maritima) and hydrangeas.
Among evergreens that do well are loblolly pine, Eastern white pine, mugo pine, almost all junipers, and southern magnolia. White oaks, live oaks and scarlet oaks are good deciduous trees.
Perennials that do well include blue flag iris (I. versicolor), phlox, lupine, blanket flower (gaillardia), chrysanthemum, rudbeckia and goldenrod.
A few other low ornamental plants that thrive are honeysuckle vine, annual lisianthus flowers (Eustoma) and yucca, a sharp, sword-shaped, southwestern-looking evergreen sub-shrub.
Some plants that aren't native have become naturalized and are highly successful in a beach environment. They include daylilies, lilacs, rugosa roses, santolina and Japanese black pine.
A reader who's building a house on Cape Cod sent me an e-mail recently asking what to plant on a sunny lot near the ocean. He wants some yard and was looking for recommendations on ground covers and low-maintenance plantings.
He has already rejected English ivy and pachysandra, which is a good thing. With a little shade, sedges (Carex species) would be good, as would edible, lowbush blueberry (Vaccinium angustifolium). In sun, there are dozens of native grasses, heath, heather, other low-growing shrubs, bearberry (Arctostaphylos uva-ursi), sea oats, sea lavender and creeping juniper. Because they are native, they are used to local conditions and don't require fussing over.
Nurseries near the shore are good places to ask for advice, as they can help you identify what is native and what does well.
This reader also asked if there are any books about seashore gardening. There are not a lot. Here are a couple to look for:
* "Common Plants of the Mid-Atlantic Coast: A Field Guide," by Gene M. Silberhorn (Johns Hopkins University Press, 1982)
* "Taylor's Guide to Seashore Gardening," editor Frances Tenenbaum (Houghton Mifflin, 1996)
* Out of print but being reissued by the end of the year: "Gardening on the Eastern Seashore," by R. Marilyn Schmidt (Barnegat Light Press, 1983); also out of print but worth looking for in used-book stores, "Seashore Gardening with Native Plants," by R. Marilyn Schmidt (Pine Barrens Press, 1997). A new edition of this is in the works, perhaps in time for Christmas.
Almost every state and many geographic areas have Web sites devoted to native plants. The New England Wild Flower Society at www.newfs.org/nps.htm links you to an extensive list of native plant societies in the United States and Canada. Collectively, they offer tremendous plant resources.
Joel M. Lerner is president of Environmental Design in Capitol View Park, Md. E-mail or contact him through his Web site, www.gardenlerner.com.