Hypericum prolificum hy·pe·ri·cumprolificum uncommon noun 1. stiff shrub having oblong entire leaves and dense cymes of yellow flowers Synonymsshrubby St John's wortHypericum prolificumHypericum spathulatum Related words Broader terms St John's wort WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.