BY THE SEA
by PATRICK CHASSE
The sheltering effect of the house and hedgerow combined with good choices in plant material-hydrangea and lavender-make this seaside garden a success.
Large trees make a good salt and wind block for this cutting garden. The fence provides a barrier against deer while buffering the wind.
The edge of the sea has always held a magnetic appeal to humans. It is one of the most dynamic and picturesque of landscapes. Yet those who live on the shore often find their homes and gardens in conflict with the coastal environment. Primary forces—light, water, rhythmic cycles, and other natural phenomena—act on the coastal zone in peculiar, particular ways. Freezing and thawing, high and low tides, rain, snow, ice, and winds create a series of challenges for each living component in the shore ecosystem. These patterns offer both the support and the stress that have shaped the indigenous biological communities, whose members have evolved to tolerate and even capitalize on such extremes of exposure. By observing the physical elements of the shore garden site and the extreme forces that influence it, we can create a fitting design and achieve horticultural harmony, as we find inspiration in seaside ecosystems and indigenous plants.
At the shore, the physical substrate—that is, the character of the land underfoot—is bound to present difficulties for the gardener. A rock-based shore is stable, but suffers from extremes in moisture and temperature, and its shallow soil offers poor anchorage for roots. Sand, on the other hand, forms an almost fluid substrate. It shifts and drifts with wind and waves, and it is readily threatened by a high water table. Meanwhile, the chemical character of any soil on the site, which arises from its underlying geology, will have done much to determine what sort of plants are growing there already.
Trying to alter the basic structure of either a rocky or a sandy shore can result in physical destabilization or worse. Tread lightly. Likewise, many types of sensitive shore habitats are protected from disturbance by state and local environmental laws, so give up your dreams of a putting green or a rose garden in a marsh, estuary, or barrier beach.
The best guide to what plantings might be possible and appropriate for your shoreline site is the biological community already present. If the site is reasonably undisturbed, members of the community have evolved to survive its specific conditions, and you should note them well. The evergreen juniper, for example, can tolerate salt spray, wind, drought, freezing, and other harsh shore conditions. Choosing plants with similar physiological characteristics is a good way to find sympathetic new candidates.
The great challenge to shore plant communities is salt. The accumulation of salt in the groundwater and in the surface layers of the soil can be a serious growth deterrent. Although salt along the shore is usually flushed away by rain, mechanical irrigation may be necessary to keep the soil adequately salt-free for garden plants, especially in times of low rainfall. Make sure you have enough supplementary water before building your fantasy seaside garden. It can be a great shock to see a garden pickled like a salt cod in a drought year.
Not just a threat in groundwater and soil, salt goes airborne in sea spray, and desiccates most land plants, burning tender tissues.
There are three major mechanisms that make plants more salt tolerant: a coating of fine hairs that shield leaf surfaces from direct exposure; a waxy layer that seals the leaf surface; and an ability to use water resources more efficiently. This gives points to silver-foliaged plants like artemisias, waxy-leafed plants like bayberry and inkberry, and xerophytic or dry-condition plants such as dune grass. Plants from similar environments elsewhere are also likely to thrive—the ubiquitous Rosa rugosa, for example, which grows wild along so much of the East Coast, is originally from Asia.
SHELTERING THE SPACE
Besides salt, persistent winds and freezing rain are major impediments to plant growth. Creating a sheltered space for garden plantings will increase their health and offer a chance for more variety. Hedges of salt-tolerant evergreens, beach roses, or sumac can protect leeward plantings. Even better, if space allows, is the agricultural technique of shelter belts of dense trees, which can add privacy and a substantial scale to the landscape. Fences are more visible, as are freestanding stone walls; apparently contrived, they can undermine the natural effect. Many towns consider fences “built structures” subject to height and setback rules. A good dodge, observed in an Olmsted-designed garden, is a three-foot-high fieldstone retaining wall, gently bermed to the top on the ocean side and planted with tough shore plants. This berm-wall provides an aerodynamic landform as well as some hedge protection for a garden planting bed set to the inside of the wall.
Buildings make good wind baffles, despite creating some downdraft eddies. Using the house, the garage, and any other outbuildings to protect and fortify a garden against harsh elements is a double winner. Intimate views of the garden from the house bring nature indoors and provide pleasure even in winter. Connecting buildings with sections of fence can further protect a garden space—without creating the Fort Apache look of a freestanding fenced garden compound.
The final thing to consider when making a garden near the sea is the often unanticipated problem of resident wild creatures, large and small. Seagulls, sandpipers, and seals are usually thought to be pleasant features of the coast, and don’t compete with the serious gardener. But deer, rabbits, woodchucks, raccoons, voles, and other marauders regularly ply the shore in search of tender vegetarian fare. Thinking defensively about how you might be able to scare them away or exclude them altogether (a better but more expensive route) must be done before the garden is designed or built. The military term defensible perimeter really applies here. Trying to deal with the problem retroactively, after the garden has been discovered and pillaged, is frustrating and probably fruitless.
One solution is to first create a core garden, like the central keep of a castle, then surround it with rings of less important and more readily sacrificed plantings. The buildings-and-fencing approach works well here. Such a design also offers the possibility of gracefully cutting back the size of the garden later, if the work load gets to be more than you can manage. You have a template for building—and a template for backing out. So plan ahead: don’t let the seaside push you over the edge. H