The Tree Care Group of volunteers have been renewing the plantings in the various orchards and forest gardens around our site over the last couple of years. These gardens are along the Northey Street boundary and to the west of the allotment garden area.
So, what is a forest garden and how does it work?
An interconnected system
A forest garden is a polyculture or mix of different perennial plants that aims to produce food without needing a lot of added fertiliser or water, by mimicking the processes of a natural ecosystem. Mutually beneficial plants are grouped together to form an interactive community called a guild. The plants are all chosen to do well in our subtropical climate.
Layers
In a forest garden, there are groundcovers, herbs, shrubs, vines, small trees and larger trees, all arranged to capture the sun’s energy while also providing shade for those plants that need it.
Interplanted
Between the larger fruit and nut trees are smaller plants that support their growth and productivity:
- Legumes ‘fix’ nitrogen from the air into the soil, from where it is taken up by the roots of the fruit trees. Legumes include ice cream bean, pigeon pea, crotalaria, and pinto peanut.
- Nutrient accumulators’ deep roots bring up important plant nutrients such as calcium from the deeper soil into the topsoil. Nutrient accumulators include comfrey and yarrow.
- Host plants for butterflies and moths provide food for caterpillars, which recycle leaves into soil, attract birds and develop into butterfly and moth pollinators. Host plants include native mulberry, acacias, native grasses, sennas and saltbush.
- Insectary plants provide pollen and nectar for insects that pollinate food plants and for insects that feed on and help control ‘pest’ insects that eat food plants. Insectary plants include rosemary, sages, native grasses, and nasturtium.
- Ground cover plants protect and enrich the soil and stop weedy ground covers from taking over. Ground covers include pinto peanut, Brazilian spinach, sweet potato, mother of all herb, dianella, warrigal greens, myoporum, comfrey, yarrow and pepper leaf.
- Mulch plants are regularly ‘chopped and dropped’ to smother weeds and protect and enrich the soil. Mulch plants include vetiver grass, Qld arrowroot, pigeon pea and lemongrass.
Productive and resilient
Many of these support plants also produce food while other smaller perennial food plants add to the food yield as well.
A number of the support plants are local native plants that support a greater number and diversity of insects, lizards and birds than exotic plants. They help control any population explosions of ‘pest’ insects that could threaten the food plants.
Always changing
The forest garden changes over time, as faster growing fruit trees such as bananas and pawpaws mature and produce food and then die back to let the slower growing trees, like citrus and avocado, emerge.
How does it work?
A forest garden achieves its aims by:
- placing plants carefully in relation to each other to facilitate interconnection and support
- recycling plant nutrients through the soil to the root zone to feed the food plants
- building a rich, spongy soil that holds water
- supporting abundant microbial and insect life in the soil and on the plants.