Shrub is a perfectly good botanical term (with Latin equivalent, frutex) for
a woody plant that branches from the base, as opposed to a tree, which is
technically a 'single-stemmed' woody plant - both of course having the
"permanent set of woody stems and branches that continue into growth each
season". There is of course a continuum between shrubs and trees in terms of
growth form and the distinction is very artificial.

John Grimshaw