Overcome The Challenges Of Gardening By The Sea

A couple from “The City” that I’ve known for many years has recently decided to give it up—and move to The Hamptons. The only problem is that the house they fell in love with is but a stone’s throw to the bay, and the soil on the half-acre, well, it’s probably not fair to call it soil. Their first question was not about taxes (though they are far from wealthy), not about the local schools, traffic, hurricanes and all of those things that you might want to know about before moving to a new seaside community.

Their first question: “Will anything grow in the sand?”

Well, gardening by the sea—or any body of salt water for that matter—is among the ultimate in horticultural challenges. If the wind doesn’t get you, the salt does. And just when you learn to cope with both, a hurricane comes along and wipes out years of work. But some, if not many, of the most beautiful and lasting landscapes that I’ve had the pleasure of visiting have been right here, by the sea.

By the same token, we are both blessed and cursed with what is referred to as a “maritime” climate. This is one whose summer and winter temperatures are tempered by the surrounding water and nearby Gulf Stream. As a result, our summer temperatures run 10 to 15 degrees cooler than similar latitudes and our winter temps run 10 or more degrees warmer than similar inland latitudes. Interestingly though, some areas, such as the Pine Barrens, can be as much as 10 degrees cooler in the winter than spots just a few miles toward the center of the island.

Many plants will grow along the seashore and many exquisite and elaborate gardens exist within 200 feet of mean high tide even though the general public never sees nor hears of these masterpieces. In virtually every case these gardens have three basic factors in common.

First, the soils have been enriched, either recently or over generations of planting and cultivation, with generous amounts of humus or compost, and if you’re real lucky, some imported topsoil.

This, of course, assumes you want to do the ecologically incorrect act of changing the environment rather than learning to deal with what nature has dealt you. But if you have a strong back, a few years to patiently work on planning, composting and observing what grows naturally in a similar undeveloped lot, then you can save a bundle, learn a great deal and create your own seaside paradise.

The second point that these gardens share in common is the almost constant presence and exposure to salt in concentrations high enough that I remember my brand new 1979 Toyota corroding and the metal being so compromised that in only a few years the paint would flake off to the touch. The salt is present for nearly half the year on winds off the ocean that deceivingly cool us off. At other times, the ocean itself provides the salt as waves 8 to 20 feet high during furious nor’easters deposit the salt spray a mile or more inland.

And of course, there’s the salt water itself, which over the years has crept closer and closer to our homes causing many to abandon their water wells in favor of municipal water where it’s available. Saltwater intrusion will only get worse as climate change continues and the seas rise.

Thirdly, there is the problem of wind, which is a subtle villain, except in those occasional years when it turns to hurricane force. For approximately half of the year we receive cold winds out of the northwest, which result in springs that can be as much as three weeks later than in communities only 40 miles farther west. These winds can last into late May, and in unprotected areas the velocity precludes the planting of most spring-flowering bulbs and a wide range of early perennials.

As if on cue, the winds shift on or around Memorial Day to a southerly direction, often bringing the late spring fogs caused by the warm southerly air being brought across the still cool Atlantic. There are days when you can stand on the beach and watch the fog bank hang just off the coast as it teases the shoreline rose gardens with the threat of mildew and blackspot. As biting and cold as we humans find the northerlies, it is the southerlies that the plants respond to most permanently. You can see both deciduous and coniferous trees leaning away from the summer wind in a perpetual slant toward the north.

This is most noticeable as you drive down the roads leading to the ocean. You notice that the closer you get to the beach, the shorter the trees are and they tend to lean away from the prevailing summer winds. This is very obvious on Halsey Neck Lane in Southampton as the deciduous trees shorten, lean to the northwest, and then shorten more as you approach Meadow Lane.

Admittedly, it is not always possible to protect plants from these three hazards. It is therefore advisable to seek out those plants that apparently have survived the process of natural selection and can survive seashore conditions better than others. Bayberry, eastern red cedar as well as the Rugosa rose, beach plum, beach pea, prickly pear cactus, Yucca, Artemisia, sea lavender, seaside goldenrod and the sea buckthorn grow within reach of saltwater spray and so are among the best of plants for seashore gardens. But there are dozens and dozens more.

One summer as I walked out on a dock into Shinnecock Bay, I was excited to find sea lavender flowering in a tidal marsh—in a foot of salt water. I’ve also seen it submerged with flowers in full bloom above the water at high tide in Shinnecock Bay. However, one thing that gardeners do not like to do is limit themselves to a few plants, so our first task is in dealing with the soil, which can contain as little as 2 percent organic matter.

Sandy soil retains little water, especially when exposed to the previously mentioned winds; hence, most ornamental plants attempting to grow in it are subjected to soil that dries out rapidly. It is the humus in soils that aids in the retention of water and the more of this that can be worked into sandy shoreline soils, the more kinds of plants that can be grown.

Peat moss, compost (and more compost), decayed manure, and other organic matter are all helpful in creating a soil that will retain water longer than the normal sandy soil of the shoreline.

The use of mulches can’t be overlooked either, as the mulch reduces direct evaporation from the soil as a result of exposure but it also keeps the soil cooler and adds organic matter. Here, too, though, the expense of mulches must also be considered, as does the mulch quality.

Added to the problem of only small amounts of organic matter in shoreline soils is the need for added nutrients for establishment and maintenance. But keep in mind that native seashore plants need little to no nutrients once established. When necessary, organic fertilizer is the nutrient of choice as it is released slowly. But don’t be under the misconception that because it’s organic it can’t pollute the shallow water table and bays. It can.

We should all remember, however, that rapid leaching through these porous soils results in the rapid downward movement of nitrogen and to a lesser degree phosphorus, thus posing the very real problem of fertilizer pollution of adjacent bays and even the immediate ocean coastline.

There are a number of good books on gardening by the sea (GBS) and all have extensive plant lists, but the classic is Daniel Foley’s “Gardening by the Sea” (1982). You might also find a copy of “The Salty Thumb” published in 1967 by the Montauk Village Association and don’t overlook Beth Chatto’s related classic “The Dry Garden.” Keep growing.”