Multifunctional Living Fences
The following is the original version of my article “Living Fences: How-To, Advantages and Tips”, published in the October/November 2010 issue of Mother Earth News. It was one of the two articles that drew more reader comments and queries than any other I’ve published in Mother Earth News. (The other was an article on dealing with crop damaging insects without toxic pesticides, now available as Insects in the Garden: Toward a Balanced Insect Ecology.)
Fences can be essential on the homestead. They define property boundaries, separate production zones (garden, pasture, orchard) inside the property, provide privacy, and ensure security from animal (and perhaps human) intruders. They confine livestock where we want them, and protect them from predators. They protect crop areas from both wild marauders, such as deer, and from our own animal allies such as sheep and goats.
Our first inclination when planning a fence might be to choose among the many options of manufactured fencing: woven wire, electric wire, welded livestock panels, boards on pressure-treated posts, even virgin or recycled plastic. As the energy crisis deepens, however, such options—requiring a great deal of embodied energy both in terms of their manufacture and their transport over great distances and installation in the back forty—will become less readily available and more expensive. Moreover, any manufactured fence requires ongoing maintenance—painting, patching, replacing rotted posts or rusted wire—and eventually succumbs to the ravages of time, however conscientious our efforts at upkeep. Many of the materials for production of fencing (chemical preservatives for wood, galvanizing for metals) and their maintenance (painting) are associated with possible toxic spillover effects in the environment.
Most importantly, manufactured fencing is a “one for one” solution. A woven wire fence meant to contain livestock, for example, provides that service and nothing more. The key to success on a more self-sufficient homestead that aspires to imitating natural systems, however, is finding solutions that simultaneously solve more than one problem, provide more than one service, support more than one project—creating integrative patterns, synergies, and greater efficiencies not available otherwise. Enter “the living fence.”
A living fence, often traditionally called a hedgerow, is a permanent hedge tight enough and tough enough to serve any of the functions of a manufactured fence—privacy and security, livestock control, protection of crops—but which offers many biological and agricultural services the manufactured fence cannot. A living fence is an excellent example of “edge habitat” so supportive of ecological diversity on the homestead. As more species find food and habitat there—insects, spiders, toads, snakes, birds, mammals—we are more likely to see the emergence of natural balances advantageous to us, which may yield for example reduction of problem insect or rodent populations.
Depending on species used, living fences can in addition provide food and medicines for people; feedstocks for production of biofuels; fodder for livestock. Indeed, appropriate fodder trees can be even more productive of livestock feed value than pasture on a per-unit basis; and the foliage of some of them contains more protein than that quintessential protein forage crop, alfalfa: elder, Chinese chestnut, mulberry—while willow and honey locust are not far behind. Livestock also benefit from the shade of a dense living fence.
If we include leguminous and other nitrogen-fixing species in the fence, nitrogen will be added to the soil throughout the root zone—and some of that nitrogen can be harvested as well in the form of leafy cuttings for mulches and composts.
Living fences can make a major contribution as windbreaks, reducing wind stress on livestock or crop plants, drying of soils, and wind erosion. (A six-foot high hedge will provide these protective effects over a downwind distance of 100 yards.) It has even been argued that a field sheltered by a living fence will retain more CO2 at ground level, to the benefit of pasture plants or growing crops, which respond with increased yields.
As well, they contribute to buildup of humus in the soil, not only through breakdown of leaf litter, but through root hairs shed to balance loss of top growth each time they are pruned or grazed. If sited along contours, hedges can eliminate rainfall erosion on slopes.
Living fences can last far longer than manufactured fences, as long as the natural lifespan of the species used, which in some cases can run to hundreds of years. Many appropriate species coppice—send up abundant new shoots if the main trunk is cut—so the fence renews itself readily following injury, and can be managed to produce wood for fence posts, fuel, construction, and tool handles and other implements.
Establishing living fences can be labor-intensive—think of planting 450 seeds or cuttings per 100-yard stretch of fence. Much care is needed before the fence is well established, to protect it from deer or domesticated grazers, and keep it from being overgrown by weeds and other competitors. Regular, severe pruning of the mature fence may be essential. Of course, if we are using the prunings for livestock fodder or mulches or fuel wood, this chore is hardly lost effort. In some cases, pruning can be left to grazing livestock.
Living fences have typically been established by planting appropriate shrub or tree species—either as started nursery plants, stem or root cuttings, or directly by seed—at much closer spacing than would be used in any other application. As they mature, they are pruned hard to force thick, bushy growth, to form an impenetrable hedge.
Another fascinating option is to join the individual plants into a single living whole by osculation (or sometimes inosculation—in either case, based on a Latin word meaning “kiss”). The young trees or shrubs that will make the fence are planted at four to eight inches, depending on the species used and the desired height of the fence. As the plants grow, the branches are tied together. The inner bark may be exposed with a knife, but with inosculate species the abrasion of the bark of tied branches as they move in the wind usually causes the branches to grow together in a natural graft. (Crossing branches not tied, even crossing roots, may bond as well when the plants are so tightly planted.) The result is a closely meshed barrier that grows stronger and more resistant each year. And it is a single living entity: Each individual plant in the fence is now part of one continuous vascular system—should the roots under any single plant die, its top growth continues unaffected, supported by the other plants with which it has inosculated.
A wide range of species—trees, shrubs, vines—will inosculate, and thus are candidates for use in a living fence: elm, a number of the oaks, olive, peach, dogwood, beech, hornbeam, almond, crab apple, hazel (filbert), a number of the willows, sycamore, grape, and wisteria. Trees with pliable branches are especially suitable, with apple, hawthorn, pear, and linden being among the best.
Choice of species depends of course on many things: purpose of the fence, possibilities for multifunctionality, and climate. For example, farmers in southern Mexico uproot organ-pipe cacti (Stenocereus thurberi) and set them in the ground as closely spaced fence posts. The trunks establish new roots and proliferate, forming a thorny, impenetrable living barrier. In the radically different climate of New Zealand, tree ferns are similarly transplanted in a row. When they re-root, they form a beautiful and functional living hedge.
A couple of species that are widely adaptable in temperate zones illustrate the possibilities for multifunctional living fences. Jujube (Ziziphus jujuba) is a native of Central Asia that is suitable for Zones 6-9 in this country. It thrives in poor soils and severe drought, though is even more productive in better soil and more generous rainfall. In living fences (as it has been used in India, China, and Australia), it can be kept to 4 to 6 feet with pruning, or allowed to grow as high as 30 feet. Fast-growing, it fruits precociously: A young potted tree I planted two years ago (northern Virginia, Zone 7a) is covered with fruit as I write. The fruit—like a large date or small apple—is mildly sweet, pleasant, nutritious, and easily dried for storage without energy-intensive processing. Both fruit, leaf, seed, and root have been used medicinally in various Asian medical traditions; the leaves make excellent livestock fodder; and the dense wood is excellent for fuel, charcoal, and making agricultural implements.
Tagasaste (Chamaecytisus palmensis) is a native of the Canary Islands—where farmers have long relied on it as a key fodder crop in their long hot, dry growing season—but is now widely planted in any Mediterranean climate, such as in Australia and New Zealand. (Much of California and other parts of the American West should be entirely suitable to tagasaste. Unfortunately I do not know of any use of this plant in agricultural fencing in the United States.) A deep-rooted nitrogen-fixer, tagasaste does well on a wide range of soils, even quite poor ones so long as they are well drained, and handles drought well. Planted as a dense, fast-growing hedge, tagasaste comes into full productivity in about three years from seed or cuttings, and recovers quickly from cutting or heavy grazing. Indeed, frequent cutting or browsing ensures that the hedge remains bushy and at a manageable height. Sheep and goats will kill the plant by stripping its bark if left on it continually; however, they can be grazed intensively on it (eating the tender growth first, before going on to the tougher, older tissues), then rotated elsewhere. Cows will not kill a tagasaste fence if left in it continually. The foliage is 20 to 27 percent protein, and is relished by many livestock species, including pigs and poultry. It coppices readily, and the wood is fairly good fuel. It blooms early, and can be an important forage plant for honeybees. It has been used extensively in drier regions as a windbreak and shelter belt. In Australia, tagasaste hedges, which remain in leaf year-round, are used as a green firebreak.
Depending on species, a mature living fence becomes a stout barrier, impenetrable by larger animals. But suppose the fence is exposed to browsing by deer, or must contain their domesticated cousins, goats? A fence with stout thorns will provide the best deterrent to excessive browsing.
Hawthorns (Crataegus spp.) are small trees with stout thorns for a self-defense fence. They produce berries that are edible (by wild birds and people), and are used medicinally. (Modern research has born out the efficacy of both flowers and berries as a heart tonic, for example.) When managed as a living fence, hawthorn can make a completely stock-proof barrier which deters browsing. Its wood makes good tool handles, turned items, and fuel.
Blackthorn (Prunus spinosa) was traditionally used in Britain and northern Europe to make a hedge whose “savage thorns” contained cattle while preventing destructive browsing. The fruits, called sloes, are similar to damson plums and can be used to make jams and preserves, or wine. The hard wood is used for tool handles and canes and makes an excellent slow-burning firewood. The traditional Irish walking stick or club, the shillelagh, is made from a blackthorn stem.
Other thorny species that could be used in living fences are pyracanthas and hollies (which provide birds and other wildlife nesting sites, shelter, and berries as food), black locust (also sets nitrogen), honey locust (Gleditsia triacanthos, whose high-protein seeds and pods make excellent livestock feed, and can be eaten by people as well), prickly ash (Zanthoxylum americanum, whose seeds are used medicinally and as a pepper substitute), and rugosa rose (whose fruits or “hips” are so high in Vitamin C that herbalists sometimes classify them as medicinal, sometimes as a “superfood”). Jujube, already mentioned, is thorny as well.I’ve read claims that the right choice of species yields a fence that deters even cats and raccoons!
Thus far the discussion has focused on individual species we might use to form a living fence. There is no reason, however, that we shouldn’t mix different species as needed—the possibilities are endless. We could set the larger trees—fruit or nut trees, for example—at much greater spacing than for the tightly planted hedge fence; and fill the gaps with lower growing plants discussed earlier, with species choice dependent on our needs (foods and medicines for people or livestock) and concerns for the local ecology (wild habitat and food sources) and pressures from wild competitors like deer (thorny barriers). Rugosa rose and brambles, for example, might serve all these functions.
There has been little traditional use of living fences for agricultural purposes in this country (though of course their use for ornamental landscaping is common). This is odd, given their extensive use in Europe, since colonial America was settled largely by Europeans. Actually, George Washington did attempt to carry on that tradition at Mount Vernon. Like modern gardeners and orchardists, his horticultural efforts were thwarted by deer and other marauders. He envisioned living fences to exclude them, planted with weeping willow, yellow willow, Lombardy poplar, or cedar. As revealed in one of his diaries, however, the species he settled on as the most suited to his purpose was “ . . . Honey locust; the seed of which not to be put more than Six Inches a part; that when they get to any size they may be so close, stubborn, and formidable, as to prevent an [incursion by ‘preditors’]; indeed I know of nothing that will so effectually, and at so small an expence, preserve what is within the Inclosure, as this plant.”
Apparently he had in mind “entwining them as they grow up” (or pleaching) to make a stoutly secure fence. But a motivation as well was a desire for greater efficiency, and a concern that the extensive use of split-rail fences was already putting intense pressure on forests in his area. Growing living hedges in place was thus “indispensably necessary to save timber and labour.”
Since Washington’s time, the major application of living fences has been the extensive use of Osage orange (Maclura pomifera), discovered by the Lewis and Clark expedition and planted extensively in the central and eastern United States in the 1800s (before the invention of barbed wire), especially to fence the rapidly-colonizing prairies. After the Dust Bowl disaster of the 1930s, Osage orange was used to plant thousands of miles of shelterbelts to prevent wind erosion. For a large, incredibly tough and enduring windbreak that becomes a major player in the local ecology, probably nothing surpasses Osage orange. A typical start to such a fence was the planting of a single row of Osage orange trees one foot apart, and its protection in the first few years (it is quite sensitive to browsing when young), to produce a fence that was “horse-high, bull-strong, and hog-tight” in four years. Farmers who took the trouble to weave together the already intertwined branches for more pleaching would create an even more impenetrable barrier.
Osage orange is easily propagated from seeds, cuttings, or sprouts from the roots. It is tolerant of a wide range of soils, resistant to drought, long-lived, and little affected by insects or disease. Sharp, stout thorns on mature growth prevent injury by browsing deer or livestock. It is possible with a couple of severe prunings a year to keep an Osage hedge to four feet high by two feet wide. Without hard pruning, however, it will rapidly grow much taller. Since it coppices vigorously, farmers of the past clear-cut sections of fence on a ten- to sixteen-year cycle for fence posts (about 4000 per mile) that are immune to termites and are the most resistant to decay of any North American species—Osage fence posts have been known to stand in the soil well over fifty years without rotting. The wood, heavy and strong and hard, was previously used to make hubs and rims of wagon wheels.
Since the death of George Washington’s dream of farm-gown fences, Americans exploiting an incredibly rich continent and rapid technological innovation have usually preferred man-made fences to living ones. As we enter a new age of limits, however, we may rediscover the benefits of growing our fences in place: greater reliance on local and homegrown resources, a more diverse and balanced ecology, and a more sustainable agriculture.
It is likely that a greater reliance on hedgerows for agricultural fencing would have profound social and cultural effects as well. Large hedgerow projects are significant undertakings that require a lot of initial planning and effort, become a major part of the local landscape, and span generations. More extensive use of living fences would probably encourage a change in our land ethic, with a greater sense of farm integration and farm family continuity, and with a strong tendency for the community to have a sense of investment in local hedgerows.In Schleswig-Holstein, Germany, for example—one of the classic hedge regions—boundary hedges traditionally took up about five percent of agricultural land. Farmers whose land abutted a hedgerow were forbidden by law to cut their side of the fence indiscriminately, thus exhausting it. However, on a sustainable schedule, each farmer harvested fuel wood from the hedge. The result was that, in addition to all the other benefits of hedgerows, farmers in Schleswig-Holstein—with less forest than any other part of Germany—were able to supply their needs for firewood.