Meaning: seek something diligently; also, work hard to achieve something.
Example: Sales department knows, when earnings are down you beat the bushes for leads.
Origins: From hunting practice of flushing birds from hiding by hitting bushes with a stick.
Source for meaning and origins.
Rewrites: beat the flora beat the shrubs                          thrash the chaparral whack the vegetation jostle the low hanging fruit wake the early birds
Discussion: I’ve attempted to address both the original wording and the nuances of meanings. See what you can do.