Word Origin & History
type of flowering plant, so called from 1690s. In the sense of "person excessively sympathetic" (esp. toward those the speaker deems not to deserve it) is attested by 1951, but said by many to have been popularized with reference to liberals (especially Eleanor Roosevelt) in 1930s by newspaper columnist
Westbrook Pegler (1894-1969), though quotations are wanting; bleeding in a figurative sense of "generous" is from late 16c., but the exact image here may be of the "bleeding heart of Jesus."