KEEL: The lower, pouchlike lip of flowers of certain members of the bean family. The keel is formed by the fusion of two petals. The boat-shaped structure formed by the two lower petals of many members of the Leguminosae.
KERNEL: The edible part of nut.
KNOCKING OUT: The temporary removal of a plant from its pot in order to check the condition of the root ball.
KNOT GARDEN: A very carefully planned garden of small dwarf shrubs or even herbs. Planned in a pattern and kept in order by constant pruning and trimming.