The Shrub Forest Layer
Shrubs are perennials with a permanent framework of woody growth that stand lower in stature than the trees of the canopy layers. While trees have a single woody stem and grow upright and tall, shrubs typically have multiple woody stems that branch out and do not grow as tall. Shrubs that provide fruits or other edible yields, and nitrogen-fixing shrubs are among the important plants within this category when designing a food forest or another agroforestry system.
In focussing on trees for a food forest, many spend less time thinking about the shrubs that might also be included within the system. But selecting the right shrubs for a forest garden or food forest design can really make or break the design as a whole – especially when it comes to temperate climate permaculture.
Plants that have a persistent woody framework but which are shorter than trees and typically multi-stemmed rather than single-trunked, shrubs might not be the stand out stars of a food forest, but they can definitely be among its most important plants.
The Shrub Layer of a Food Forest
Shrubs in forest gardens nestle below the trees within the system, and may also have herbaceous plants beneath. Climbers can also be trained to grow up through the shrubs within a system.
Careful consideration is required to make sure that shrubs do not compete too much with your key tree species, nor with other planting.
It is also important to think carefully about access and practicality when it comes to tending and harvesting your forest garden, since an ill-placed shrub could really make things a bit difficult for you.
As with the placement of trees and larger shrubs, those shrubs that you place within the shrub layer of a food forest or forest garden must also be placed with careful thought about the setting and environment, and, perhaps most crucially, sunlight and shade.
The Functions of Shrubs in a Food Forest
Shrubs within a forest garden are often chosen primarily either for their edible or useful yields to us, or for their use within the system as a whole.
In a food forest or forest garden, shrubs might be important as:
- Food producing species (for berries/ fruits, nuts, edible leaves etc..)
- Medicinal or otherwise useful species (for herbal remedies and numerous other tangible yields).
- Flowering species to attract pollinators and other beneficial wildlife.
- Species to boost fertility (such as nitrogen fixers, plants providing biomass to improve the soil etc...).
Many shrubs can be useful in these ways, and some can be important in more than one, or even all of these ways.
When and Where Shrubs are Used in a Food Forest
However, not in all cases will larger shrubs be incorporated in the same way. Shrubs can be a part of many food forest designs but can be included in different places in slightly different ways.
Shrubs might be included:
- Below the canopy - within the drip-line zones of trees.
- In sunny glades within the scheme.
- Flanking pathways within a food forest.
- Along a boundary edge of the system.
- In a linear food forest design with trees.
Shade-tolerant Shrubs for Below the Canopy
The degree of canopy cover within a design will often dictate the location of shrubs as well, of course, as the shrubs that are chosen for the design.
The degree of canopy cover in a system depends on the location. Typically, there will be a greater degree of canopy cover in tropical, subtropical or warmer temperature climates than there is in cooler temperate zones.
Often, a starting point can be examining native woodlands or forests to see which shrubs grow in the shade below the trees. Native species may have desirable attributes and provide yields for us, and so may not need to be replaced by productive, non-native species to create a food forest or forest garden.
When choosing shrubs for shade, it is important to think about the degree of shade they would have to deal with. Think about the trees above them, and the density of their crowns. How much light really can penetrate? How does the amount of light alter throughout each day, and throughout the year?
Some shrubs are suited to light or dappled shade. Some can cope with partial shade. And some truly are shade-lovers that can cope even in very deep shade. So it is important to choose the right one for the environmental conditions you have, or plan to create in your food forest or forest garden.
Placement of Shrubs for Optimal Light in a Food Forest
Especially in a cooler temperate climate, introducing lighter, brighter areas into your food forest or forest garden can be important. Shrubs will often be placed where they can take advantage of light on a sunnier fringe of the project site, a sunny glade, or a smaller break in the canopy.
Shrubs will often be placed to the southern side of taller shrubs and trees in the northern hemisphere. And to the north in the southern hemisphere.
The placement of even relatively shade tolerant shrubs to catch more sunlight within the design can be important in particular when the shrub in question is one which produces fruits. Fruit bushes can be tolerant of shade but many will fruit best with more sun. And fruits/ berries will typically ripen sooner in a sunny position.
Shrubs as Path Edging in a Food Forest
Shrubs may also be used to create partial barriers between paths and growing areas, or between specific sections in a food forest or forest garden.
Lower growing shrubs may sometimes blend with another layer of such systems, and become useful ground cover. Layer shrubs can help to define where people should walk, and can also potentially also help channel wildlife where you want it to go.
Placing fruiting shrubs along pathways can also sometimes allow them to get a little more light, and also makes harvesting them easier as you make your way through the system.
Using Shrubs as Boundary Planting
Shrubs can also be beneficial in creating and defining a boundary of your food forest or forest garden. Shrubs might often be used to create a hedgerow, and a hedgerow can protect and aid the ecosystem of the food forest itself in a number of different ways.
For example, the correct placement of a hedgerow made up of shrubs and perhaps some smaller tree species can create a windbreak to create a more sheltered environment and generally improve the microclimate on the site. This may allow the trees and other plants positioned on the leeward side in a food forest or forest garden to thrive, where they may not otherwise have been able to do so.
A hedgerow-type planting scheme on the edges of the design may also serve other benefits – such as keeping certain browsing herbivores out of the newly planted area, for example. Sometimes, placing shrubs in the right way around saplings can protect these, and help ensure that the woodland/ forest system can mature.
Creating hedgerows along the edge of a food forest or forest garden can also help in creating wildlife corridors and bringing beneficial wildlife into the system itself. Though choosing a range of fruiting, native species of shrubs, we can boost biodiversity in the area.
Linear Food Forest/ Hedgerow Design
Where space is limited, and/or where you are looking to integrate the ideas of food forests or forest gardening into a broader scheme, such as in a silvo-pasture or silvo-arable setting, you would do well to remember that it is possible to create a hedgerow-like food forest.
Food forests can be linear – they do not necessarily have to spread out over a large area of land to be effective and beneficial. You might consider creating rows or double rows of trees, shrubs and other plants between pasture or arable crop planting.
Where livestock are involved, shrubs might be carefully selected in order to provide appropriate browse for the species in question, as well as for their benefits to us, and to the system as a whole.
Choosing Shrubs for a Food Forest
When choosing shrubs for a food forest, the most important thing to remember, as always, is that you are always choosing for a specific site and situation.
Make sure that you understand the conditions that you will provide where you wish to plant, and find shrubs suited to those conditions. Begin with natives, considering these before you consider alternatives that are not native to your area.
Think about where you will be using shrubs, and what you wish them to provide. Remember to look at both what the shrubs in question can provide within the system as a whole, and what they can provide in terms of yields.
Choosing the right shrubs for a food forest or forest garden design can actually be one of the more complex and challenging elements to get right. But by carefully thinking through the environment, the needs of the system and your own needs you can avoid some of the most common pitfalls and ensure that you create a system that really can stand the test of time.