On New Years Day I planted a row of blueberries along the left side of the drive at the edge of the canopy of the large oak trees in my neighbor's yard. I started preparing the soil for them 2 years ago by spreading a thick layer of horse manure and sawdust bedding along the drive and planting a cover crop of annual rye grass and red clover. The following summer the cover crop was cut down and allowed to decay adding additional organic matter to the soil. A mulch of oak leaves covered the soil until I was ready to plant the blueberries. When I dug the holes for the blueberries i found a very soft, fluffy, humus-rich soil full of earthworms. They will love it here. On the right side of the drive you can just see the 2 pomegranates and the nanking cherry that I moved from the community garden late the previous fall. In a month or so I will be adding a couple of plum trees to this forest garden on either side of the drive near the top where it meets the street.
What is a forest garden? A forest garden is a garden (a deliberate arrangement of plants grown to meet a human need) that utilizes the layers of vegetation found in the forest and along the forest edge to produce food, fiber, fuel and building materials. A forest garden can have up to 7 layers as described by Robert Hart who developed the concept for temperate climates. The uppermost layer is occupied by the canopy trees, my neighbor's oaks in this example. The understory trees comprise the next layer. The plums, cherry and pomegranates fill this niche in my garden. The newly planted blueberries will make up the woody shrub layer. Later this spring we will be taking divisions of herbaceous perennials from our bugscaping planting to occupy the space between the trees and shrubs. A groundcover layer of wild strawberries is already thriving. We will add some clover to that to help build up nitrogen. I transplanted some salsify roots from the old community garden this fall . They will produce a beautiful orange flower in the spring followed by a seed head similar to a dandelion's. The seeds will be blown all over the garden adding a layer of deep rooted plants making up the 6th layer. This garden will not have a 7th layer which would consist of vines climbing up the trees and over the shrubs.
All of these different plants taken together form a whole that is greater than the sum of its parts. In permaculture this is called a guild. All of the plants in a guild contribute something to the community or guild that benefits the whole. The trees and shrubs provide homes and food for birds, insects and mammals. Their leaves shade the lower plants and when they fall they protect the soil from erosion and through the action of the other organisms in the soil food web they recycle nutrients. When we select the plants for the herbaceous perennial layer we will include plants that fix nitrogen to be shared among the neighbors and plants that provide food and habitat for beneficial insects. The groundcovers shade the soil and help prevent erosion. The deep tap root of the salsify will extract nutrients from the subsoil and make them available to the more shallow-rooted plants.
By including plants that fill all of the niches in the community, weed species will be excluded. Having all of the surface area covered by vegetation and mulch from the leaves keeps the soil cool and allows it to absorb and retain lots of water. Providing habitat for birds, mammals, lizards, snakes, spiders and insects creates an army of defenders working to ward off pests. This system will become mostly self-sustaining after a few years.
We like that because we are getting too old to work so hard.