Peppergrass

Some of the weeds that cause an undesirable flavor in milk are: onion, tarweed, scaleweed, garlic, mustard, pepper grass.

Source: wiktionary

To this group belong feeds such as: Silage, alfalfa hay, turnips, kale, apples, potatoes, beet pulp, beet tops, rape, cabbage; and also weeds such as garlic, scaleweed, dog-fennel, tarweed, peppergrass, wild mustard, and others.

Source: wiktionary