The shrub layer and why it matters
Shrubs require less maintenance than annual vegetables, and some can produce hundreds of pounds of food each year, with almost no labor once they get established. Most will benefit from regular mulching and pruning. Many of the fiber plants fall into this category, as do most small fruits and berries. If you are planting shrubs in amongst trees to create a food forest, plant the shrubs while the trees are still young, because many of them need sun to get established. Once established, most shrubs will be relatively drought and shade tolerant and will help filter the wind through the low parts of the garden. This is important because though trees provide an excellent windbreak, if there are no shrubs, then the open space creates a cold wind tunnel, which can be rough on tender herbs and vegetables.
Shrubs are usually thought of as ornamental: gardeners often don’t realize how many shrubs are edible!
What’s the difference between a shrub, a hedge, and a hedgerow?
Regional definitions of the term “hedgerow” vary widely, so we’ll define a hedgerow, for our permaculture purposes, as a perennial polyculture planted along an edge.A well-designed, multifunctional hedgerow can provide food, shade, privacy, habitat, firewood, and much, much more. Hedgerows can create microclimates, redirect strong winds, condition soil, and shelter large areas of tender plants that might not otherwise thrive in your area. So a hedgerow is not AT ALL just a bunch of bushes–plants in every layer can make up a hedgerow,and a hedgerow can solve a lot of design problems.
Integrated Pest Management
One of the major benefits of having a hedgerow is that it creates habitat for beneficial insects. Check out this video, from the AWESOME Peaceful Valley channel. Her style of garden beds isn’t perhaps what everyone would choose, but she gives some sound advice about seed and plant mixes that will attract and protect beneficial insects.
Multifunctional hedgerows are an excellent strategy to include in an ecological garden as part of whole- system design for self-reliant living. Hedgerows consist of mixed plantings that may include trees, shrubs, low-growing plants, perennials, herbs, and vines. Hedgerows often grow along field borders, fence lines, and riparian zones in either rural or suburban settings. They enhance the beauty, productivity, and biodiversity of the landscape.
Hedgerows act as bank and soil stabilizers and conditioners; animal fodder; nectar sources for bees and other pollinators; habitat for pest predators, mammals, birds, reptiles, and amphibians; windbreaks, shelterbelts, and privacy and sound barriers; and a source of diversified income. In riparian zones hedgerows also provide shade areas that cool the water temperature. They are an ultimate opportunity for biodiversity.
Potential income producing opportunities of hedgerows include fuel wood, craft materials (such as willow), medicinal herbs, floral materials and dye plants, and seeds, rootstock, and cuttings for propagation. The leaves, berries, nuts, roots, shoots, and fungi are wonderful food sources.
One of the most useful functions of hedgerow plantings is their role as windbreaks. Wind will be affected by a planting that is only three feet high as long as it is of 40 percent density and is sited perpendicular to the wind. It can also reduce home heating costs from 10 to 40 percent. Hedgerow windbreaks can typically reduce open-field wind speeds by 20 to 75 percent at distances of up to ten times their height.
The combination of function and beauty is an essential component of all landscaping. The location and size of the area to be planted will determine hedgerow design, but hedgerows are always longer than they are wide. In placement, a north–south planting direction is ideal but not essential. Whenever possible, arrange hedgerows perpendicular to prevailing winds.
Although a single line of trees will provide some benefits, four or more rows of plants are best for windbreaks, water and soil conservation, wildlife habitat, and general biodiversity. When it works for the situation, place plants tallest at maturity in the center row, with shorter ones interplanted between and along the edges.
A diverse selection of plant sizes and characteristics is most beneficial. Through thoughtful observation, the design will match the site and plant characteristics. The elements that influence plant selection, again, are function, location, and size of a fully grown hedgerow. Planting hedgerows also encourages wildlife corridors. As an example, if you are interested in attracting birds, then include deciduous trees as the tallest plant in the hedgerow. Birds find it much easier to land in deciduous trees due to their open form.
Establishing a hedgerow is a long-term commitment. With proper planning and care, it will take approximately four to eight years to establish the planting and thirty or more years for it to reach maturity. However, it is worth the investment. Whether in a rural or urban setting, multispecies plantings provide beneficial opportunities for everyone.
Traditional Hedges and Hedgelaying
By Marit Parker
In permaculture we usually find tall, multi-species, multilayered hedgerows, designed to do all of the things. But it’s a common misconception that a more traditional-looking hedge isn’t multifunctional as well. They are.
Hedges became a common feature of the British landscape as a result of the Enclosure Acts, between 1760 and 1820, when what had been common or shared land became fields. Many of the hedges we still see date back even further.
Hedges around the edges of fields are important for wildlife, providing not just local habitat but also creating highways between rivers and forests.
What is hedgelaying?
Hedgelaying is a valuable and satisfying skill that involves cutting partway through the stems of young trees and carefully bending them over and weaving them into each other to recreate and strengthen the hedge as a stock-proof barrier.
Techniques vary in different regions because hedges also vary, with different dominant species (eg hazel or hawthorn).
If you’d like to learn how to hedgelay, conservation groups in the UK, such as The Conservation Volunteers, usually have at least some hedgelaying sessions in the winter months.
images by Marit Parker, from Cowbridge Physic Garden
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Relevant Links and Resources
Plants for a Future
If this has whetted your appetite for plant geek-dom, Plants for a Future is an online database that lists over 8000 edible and useful shrubs, perennials and trees. Originally focused on plants suitable for temperate regions, it has now been extended to include many of the more important tropical and subtropical edible and useful plants
Shrubs are woodier and need different care than green veggies or fruit trees. This article covers shrub pruning for beginners.
Some shrubs also have medicinal uses. Here’s an article about hedges in an herb garden.