Yarralumla School Forest Garden:
As part of the design for the Yarralumla school garden, a Forest Garden retrofit of the established orchard was designed by Dan. Prior to begining work the school orchard was a very neglected smattering of fruit trees with nothing but cooch grass and a few rosemary bushes growing underneath. This guild (Fruit trees & cooch & Rosemary) was not a beneficial one as the cooch suppresses the trees feeder roots and does not provide habitat or resources for the associates that the fruit trees need (pollinators, protection from pests, pest confusion). Further, the rosemary that had been planted to attract pollinators did not flower when the fruit trees did and Rosemary can also suppress and negatively affect fruit trees. Rosemary has a place in a Forest Garden, but out on the edge.
Because only Canopy Trees were present, this soon-to-be Forest Garden needed an understory to be designed as well as clumping and running herbaceous plants, plants to mine minerals and mulch that would protect the soil and favor a fungal environment that would support the trees. First a design was in order.
An understory of Black Currents, Red Currents and Gooseberries was designed to fit under the canopy trees once they reached their mature height. In the meantime we could plant more of these shrubs and move them out / take cuttings as the canopy progressed. Further, extensive native plants were incorporated to provide habitat for beneficial birds. These included Banksia marginata, Hardenbergia violacea, Kunzea spp, Gravillia sp. and more. In addition, local native acacias were added to the mix to assist the fruit trees by fixing Nitrogen which could be cycled in the Forest Garden by pruning the Acacias with the added benefit of producing nitrogen-rich woody mulch. Feijoa hedges were also added to the area because they are one of my favourite fruits and make a good hedge plant. These were under-planted with comfrey for deep-mineral cycling and dynamic accumulation and strawberries to provide a ground cover, excluding grass and generating another yield.
Around each fruit tree in the system a guild was designed. Each tree had a relatively simple guild of 2-3 herbaceous species planted to fill the available niches and support the trees. Although each guild was simple and understandable, the Forest Garden would have a high herbaceous diversity overall. Stone fruits and Apple trees both benefit all benefit from cross-polination. The following guilds were designed:
Nectarine: Cat Mint as a Runner, Apple Mint as a Runner, Comfrey as a clumper
Plum: Violets as a Runner, Tansy as a Clumper
Plum: Strawberries as a runner, Red Sage as a clumper, Comfrey as a clumper
Peach: Oregano as a runner, Orange Salvia as a clumper and Rhubarb as a clumper
Apple: Mint as a Runner, Tansy as a clumper, yarrow as a runner.
In a second drier patch, Mediterranean guilds were designed. Pomegranates were used as understory trees and placed on the forest edge so as to maintain light levels. Mediterranean herbs were used to match the patch.
Fig: Thyme as a runner, Comfrey as a clumper
Almond: Cat mint as a runner, sage as a clumper
Pomegranate: Oregano as a runner, Salvia as a clumper
The next step was smashing the cooch. A quick fix was required as a working bee was up-coming and the school wanted fast action. We used a thick sheet-mulch to smother the cooch with added compost and a wood-chip layer on the top.
While this did not stop the cooch in the end, it allowed us to generate a diverse herbaceous understory over a year. Now cooch is one of many other plants in the understory and the other plants are meeting the needs of the fruit trees. Over time as the canopy closes in, the cooch will be easier to remove.
Two years later and the Yarralumla School Forest Garden is humming with life and diversity. There are bees, lacewings, birds and loads of other insects that now make their home in the Forest Garden. Last season we yeilded Rhubarb, Rasberries, Currents and a few apples that escaped the cockatoos. This year I´m hoping for Mulberries and Nectarines as well.
- Herbaceous Understory taking off