shrub (n.) Look up shrub at
Old English scrybb "brushwood, shrubbery," a rare and late word (but preserved also, perhaps, in Shrewsbury), possibly from a Scandinavian source (compare dialectal Danish skrub "brushwood," Norwegian skrubba "dwarf tree"). Presumably related to North Frisian skrobb "broom plant, brushwood;" West Flemish schrobbe "climbing wild pea," with a base notion of "rough plant," from PIE *(s)kerb-, extended form of root *(s)ker- (1) "to cut" (see shear (v.)).