Cereal rye

Upright cool-season annual that grows 3-6 feet tall. Requires vernalization to head and produce seed. Makes a thick ground cover if planted in the spring. Do not confuse with annual ryegrass.
Managing Cover Crop Profitably Book CoverCereal rye: Managing Cover Crops Profitably (SARE Handbook Series Book 9) by Andy Clark (2007, 3rd ed.)