A plant guild is a deliberately planned group of plantings designed to capitalize on many of the principles of polyculture, intercropping, and companion planting. These being that different plants provide different functions and that by grouping plants together they can support each other with the different things that they do.
The Three Sisters
The classic guild is the "three sisters" - corn, beans, and squash. Corn provides a stalk for the bean to climb, the bean provides nitrogen in the soil, and the squash benefits from the nitrogen while shading the roots of the corn and beans.
Per Toby Hemenway's "Gaia's Garden", successful guilds can consist of as few as two plants. Guild components can be selected based on plants able to fulfill one or more of the following roles:
- Main plant (Usually a fruit or nut tree, but maybe corn or sunflower)
- Nitrogen fixers
- Dynamic accumulators (plants that concentrate a variety of minerals from the soil)
- Mulch plants
- Plants to attract insects
- Plants to bust up soil (especially compact soils)
- Barrier plants (plants that deter or prevent gophers, deer, etc from munching on the other plants)
Mimicking Plant Communities
There are several methods to design plant guilds. One of the easiest is to form a guild that mimics native plant communities. If you google "Plant Communities [Your State]" you'll probably find several docs including field guides that provide details for native communities in your area. Gaia's Garden by Toby Hemenway (or available as a PermaEthos class)
Although guilds are usually designed for the benefit of all the plants involved in cases where there is an allelopath as the primary plant the guild can be designed with plants that tolerate the toxic excretions.
Video about plant guilds