The Flowers were designed to be built at merchant shipyards, to ease the pressure on yards specializing in warships.

The initial three groups were the first purpose-built fleet minesweepers, built with triple hulls at the bow to give extra protection against loss from mine damage when working.

When submarine attacks on British merchant ships became a serious menace after 1916, the existing Flower-class minesweepers were transferred to convoy escort duty, and fitted with depth charges, as well as 4.7-inch naval guns.

[1] The latter two groups, the Aubrietias and Anchusas, were designed as submarine decoys, or Q-ships, with hidden guns and a distinctive "merchant marine" appearance.

Two members of the final Anchusa group, Chrysanthemum and Saxifrage (renamed President in 1922), survived to be moored on the River Thames for use as drill ships by the RNVR until 1988, a total of seventy years in Royal Navy service.