Stim-Root #2 has been proven to aid in the rooting of semi-hardwood cuttings such as summer flowering shrubs, woody houseplants, etc. 

A semi-hardwood cutting may be defined as a cutting that requires secateurs or pruners to cut, without having yet developed bark. 

Stim-Root, like other rooting hormones, will not make roots grow, rather it enhances the plants own ability to produce roots by supplying plant hormone at the point of rooting to help initiate root development.