Guild
A set of plants organised around a central plant (often a fruit tree).
Explanation
A guild reproduces the structure of a natural ecosystem: tree, shrub, herbaceous, root and climbing layers. Each plant fulfils a function (fixation, attraction, repulsion, ground cover). A central concept of permaculture, theorised by Bill Mollison and David Holmgren.
Refined definition
A guild is a functional assembly of plants (and sometimes animals) organised around a central plant (“key plant”, often a fruit tree), where each member fulfils one or more functions: nitrogen fixation, biomass production (mulch), attraction of pollinators, repulsion of pests, ground cover, mycorrhizal support, attraction of beneficial insects.
Key points
The classic functions of a guild
1. Central plant (main production, e.g. apple tree) · 2. Nitrogen fixers (Legumes: clover, lupin) · 3. Biomass plants (comfrey: potassium-rich leaves, as mulch or liquid feed) · 4. Pollinator attractors (lavender, borage, nectar plants) · 5. Repellents / scent-maskers (garlic, chives, tansy) · 6. Ground cover and living mulch (clover, strawberry, nasturtium). The list is not fixed, and a guild does not need every one of these roles: the tomato guild has no nitrogen fixer. Many of these pairings come from permaculture tradition. Source: Bill Mollison, Permaculture: A Designers' Manual, 1988; Toby Hemenway, Gaia's Garden, 2009.
A detailed example: the apple-tree guild
Apple tree at the centre. At the base: garlic and chives in a ring (reputed repellents against rodents and some pests, an effect documented in the laboratory, more moderate in the orchard). An outer crown of comfrey (chop-and-drop biomass) and tansy (reputed repellent). A border of borage and lavender (pollinators). Understorey: white clover (nitrogen-fixing ground cover). Permanent organic mulch.
The edge effect
Edges mix the conditions of two habitats and often host a wide diversity of species; Mollison makes it a design principle, the edge effect. Its real effect varies with species (Ries et al., 2004). In a guild, each plant creates edge for its neighbour, sun/shade, dry/moist, dense/open. It is exactly the opposite of a monoculture in rows.
Watch out for
- • Many popular guilds were described before being scientifically validated. If a plant in the ring does not seem to suit your climate or your soil, replace it with a local plant that fulfils the same function.
- • A guild is not fixed: it is a system that evolves. Pruning, dividing and replacing some perennial plants every 3-5 years is normal.
The guilds on this site, step by step
Sources
- Mollison, B. (1988). Permaculture: A Designers' Manual. Tyalgum : Tagari Publications.
- Hemenway, T. (2009). Gaia's Garden: A Guide to Home-Scale Permaculture (2e éd.). White River Junction : Chelsea Green.
- Ries, L., Fletcher, R.J., Battin, J. & Sisk, T.D. (2004). Ecological responses to habitat edges: mechanisms, models, and variability explained. Annual Review of Ecology, Evolution, and Systematics, 35, 491-522.