What to plant with garlic

4 plants that do well next to garlic and 3 to keep apart, each with its reason. 1 of the 7 have research behind them; the rest are tradition.

Good companions for garlic

Plant	Why	Backed by
Roses	Old practice said to keep aphids off roses; Arizona Extension calls it a belief, not a proven effect.	tradition
Cabbage family	Listed as improving cabbage-family growth; strong scent is said to deter cabbage pests.	tradition
Aphid-prone crops (as a border)	Garlic is often planted as an edge row because aphids are said to avoid it; untested in gardens.	tradition
Summer crops after harvest	Fall-planted garlic is dug in early summer, freeing the bed for a later crop; plan the next crop from a different family.	tradition

Keep apart from garlic

Plant	Why	Backed by
Beans	Charts agree garlic and other onion-family plants stunt beans; no study is cited.	tradition
Peas	Listed as harmed by garlic and onions in two charts, but one Oregon State article lists peas as a good garlic neighbor. Sources disagree.	tradition
Onions, leeks and chives (same spot each year)	Same family; rotate alliums to fresh soil for 3 to 4 years to avoid building up shared pests.	research

Good to know

Garlic has 7 entries, but several share the same sources. Garlic-specific pairings are thin in extension material.
Onions appear on black walnut tolerant lists; garlic is not named in the walnut pages we fetched.

Research means a university study or review found an effect, such as more helpful insects or less damage. Tradition means extension charts list the pair as common practice without a study behind it. Traditional pairs rarely hurt; just do not rely on them for pest control.

Sources (university extension):