Boston fern, Nephrolepsis exaltata (L) Schott, was treated with 50 and 80% wettable powder (WP) and 23, 27, and 40.3% flowable formulations of carbaryl in the greenhouse. The higher rates of flowable formulations were more phytotoxic than the WP. None of the formulations was phytotoxic with a single application of 1.2 g of AI/liter. Seven cultivars of Boston fern were evaluated for possible phytotoxicity after applications of carbaryl. The cultivar ‘Boston’ was the least susceptible, and ‘Compacta,’ ‘Curly Boston,’ ‘Florida Ruffle,’ and ‘Petticoat’ receive the highest phytotoxicity ratings.