The Essential Hedgerow
Note: Much has been written about non-native species used in gardening, many of which were introduced to North America as hedging plants. The unfortunate results of these introductions are evident and the argument against their use is clear. I advocate only the use of plants native to your area.
The Essential Hedgerow
When I imagine a hedgerow I picture a beautifully untamed, asymmetrical row of plants that are a riot of diversity, a place pulsating with life, abuzz with creatures, filled with activity, a wildlife community. Hedge and hedgerow are superficially alike yet are worlds apart. So what is the difference?
Both hedge and hedgerow are used to delineate one space from another as a fence might, such as the separation of public and private space, to define a property line or as a physical barrier to keep animals or people in or out. They can also create microclimates by functioning as a shelterbelt, such as a windbreak or snow fence. But these are all human-centered purposes, and that is where the hedgerow transcends the hedge.
A hedge often consists of a single species. The shrubs may flower, produce berries, or be evergreen but most gardeners seek out, above all, something that fills in well, bounces back easily from frequent pruning, and is well-behaved and predictable; in short, a monotonous monoculture. A hedgerow, on the other hand, is almost defined by diversity. Shrubs, trees, vines, perennials, and grasses can all be members of this living, working community. The greater the diversity of plants, the greater the number of creatures that will be drawn to it. A hedgerow of native species is environmentally-responsible, mimics the forest edge, provides a wildlife corridor, can serve as a windbreak or shelter belt, and can be planted to include food-producing plants such as berries, crabapples, nuts, and rosehips. It provides food and shelter for wildlife, strengthens ecosystems through diversity, and yields a variety of sensory experience for those of us fortunate to live nearby. Why would we want to plant anything else?
Planning a hedgerow involves careful thought but once established it will flourish with little attention. Naturally you will want species that will do well on your site; native plants suited to the soil, light and moisture characteristics of your site are almost guaranteed to thrive. Shrubs, trees, brambles, and vines that bear fruit or nuts will draw birds and mammals, of course. But for best food production you will want to lure insects and other pollinators too. Include plants that are known to be host plants for moths, butterflies and caterpillars, and provide flowering plants that will draw bees and ants. Dogwood (Cornus sp.), Viburnum sp., hackberry (Celtis sp.), virginia creeper (Parthenocissus quinquefolia), cherries (Prunus sp.), wax myrtle (Myrica sp.), blueberries (Vaccinum sp.) Sassafras albidum, willows (Salix sp.), trumpet vine (Campsis radicans) and spicebush (Lindera benzoin) are all known host plants of butterflies or moths; their flowers will also attract bees, ants, and other insects that birds and animals like to eat. And you can count yourself among the creatures that directly benefit from your hedgerow too, by including plants that produce food that you can eat and flowers you enjoy.
Birds will find safe and comfortable nesting spots in a hedgerow if plants that form thickets or that have thorns are included to deter predators, such as cats. Cardinals, song sparrows, mockingbirds, and doves are some of the many birds that prefer to nest close to the ground, hidden in the foliage. Hawthorns (Crateagus sp.), hazelnut (Corylus americana), devilís walking stick (Aralia spinosa), greenbriars (Smilax sp.), native roses (Rosa sp.), elderberry (Sambucus sp.), willow (Salix sp.), wild cherry or plum (Prunus sp.), sumac (Rhus glabra or typhina.), and raspberries and blackberries (Rubus sp.) are all thicket-forming or thorny species found across much of North America which can be incorporated into a hedgerow. Most produce food as well, making the hedgerow an ideal home.
Another way that a hedgerow protects wildlife is by providing a corridor by which animals can travel under cover, from one habitat to another. A hedgerow mimics the forest edge, the transitional area between an open area (usually a grassland of some sort) and a wooded area. Much of the wildlife activity in a forest actually takes place in this zone, so hedgerows play an important role in regions where the forest edge has been eliminated, such as suburban lots, parks, and other open areas. The most successful wildlife corridors will be at least 20 feet wide, which can be achieved by planting your hedgerow three rows deep. These rows would ideally include a mix of deciduous and evergreen shrubs and small trees of varying heights, with the tallest toward the center and the shortest at the edges. Once the shrubs and trees are established, perennials and grasses can be allowed to grow alongside the hedgerow, mirroring the form of the woodland edge. Adding small brush piles to the base of a hedgerow can provide additional protection for snakes, salamanders, chipmunks, and other ground-dwelling creatures.
Smaller hedgerows are worth growing, too. They can provide food and shelter for wildlife that might otherwise be unavailable, and can bring beauty to the landscape throughout the year. By including plants that flower and produce berries at different times, a steady stream of wildlife can be drawn to a hedgerow in every season. By selecting plants with winter interest, such as red-twig dogwood (Cornus stolonifera), winterberry (Ilex verticillata), or witch hazel (Hamamelis virginiana), a hedgerow can delight the eye even in the depths of winter. And soon enough, spring flowers will return.
A smaller hedgerow is easy to maintain, and managing a large one is not much more difficult (and is certainly less work than maintaining a traditional pruned hedge). However, a hedgerow does require attention every few years if it is to provide optimum food and shelter for wildlife. To preserve its ability to mimic the forest edge, try to keep height and growth in check. As trees, tall shrubs, or vines grow tall enough to crowd out smaller plants, the smaller ones may begin to die back. This actually reduces the cover at the base of the hedgerow, making small animals more vulnerable to predators. Every five years or so, prune, cut back, or thin plants that are overwhelming others. Open up an occasional gap in the hedgerow, letting sunlight and air to the base, which will allow smaller plants to grow strong and healthy, quickly filling the gap again.
When the hedgerow is healthy, it can produce more food for wildlife. By allowing sunlight to reach the various species in the hedgerow it helps each generate more food. Pruning, too, often encourages food production. For instance, lopping off the tops of pines will encourage them to put energy into pinecone production, and raspberries and blackberries are more productive when older canes are cut back. Many plants produce flowers and fruit on new growth but others do so only on previous yearís growth. By limiting your general pruning schedule to no more than once every two or three years you will make the most of the growth cycles of each.
Lastly, but for some of us, most importantly, is the natural beauty of the hedgerow. The diversity of plants that can be included virtually guarantees that every season can bring a kaleidoscope of buds, flowers, foliage, or berries. There is nothing monotonous in the variety of species that can be incorporated into a hedgerow; there are no rules that must be followed and no shapes that must be adhered to. Each species is free to express itself in its own form, and will put forth its best with only minimal guidance from you.
Often, fences and hedges can make good neighbors and are a necessary element of the landscape. Why not create one that contributes to life, instead of simply restricting it? A hedgerow does more than divide property; it provides habitat, food, and shelter for wildlife and will bring joy to you and to all those who love wildlife gardening.
Written December 2009. I will include more photos of hedgerows throughout the year.
Suggestions for shrubs, trees, and vines that will work in a hedgerow can be found here: Plants for hedgerows