In garden lingo it is what comes out the back end of aphids, scale and mealy bugs. And stool layering is not what it sounds like at all. It is actually a useful form of plant propagation where shoots are taken from a root stock that has had soil earthed up around it. Some garden words can get one into trouble if not used correctly. If the Humboldt County Sheriff's Department discovered you were growing potherbs, they might not believe the crops in question were spinach, collards and kale.
Gardeners also have a propensity to apply graphic descriptions to certain tools and plants.
They call gladiolus, glads, chrysanthemums, mums, and flowering crab apples, flowering crabs. The latter can conjure the image of a dungeness crab sprouting camellia blossoms if you lack garden-ese. A sucker is not candy on a stick or a stupid person, but a piece of plant anatomy. Green manure is green but not manure. There is also a fascination with blood in the garden.