A guild extends the concept of companion planting to a whole ‘community’ of plants which benefit, support and protect each other. For example, apple trees, comfrey and scented geranium and calendula all work together. Comfrey’s deep roots break up the soil; the scent of geraniums confuses codling moths and prevents them attacking the apples; and the calendulas attract good insects. All three smaller plants provide green mulch for the apple tree, and the apple tree in return drops apples and leaves that fertilise the smaller plants underneath. Chickens are part of this community too; they destroy pest grubs and their droppings are rich fertiliser.