Lettuce

Juglone from butternut trees inhibits growth of lettuce and can cause yellowing and stunting.

Yew produces strong allelopathic compounds that inhibit growth of most herbaceous plants including lettuce

Tarragon produces allelopathic terpenoids that can inhibit lettuce germination and growth

Vetiver's dense root system and allelopathic compounds can suppress nearby lettuce growth

Desert date produces allelopathic saponins and creates shade that inhibits lettuce cultivation

Dense duckweed mats can compete for nutrients in hydroponic systems with lettuce cultivation

Black poplar creates heavy shade and releases allelopathic compounds that inhibit understory plants like lettuce

Jatropha's toxic allelopathic compounds severely inhibit lettuce germination and growth

Osage orange root exudates can inhibit germination and growth of lettuce and other sensitive crops