Unfortunately, botanists will not make the big bucks in life, although they won't be walking the streets with that oddly smelling herb under their arm, either. When it comes to positions at research institutes—be it pharmaceutical companies or universities—plant biologists right out of college can expect to make nearly $35k a year, while full-time professors and lab chiefs tend to secure an income of about $120k. Most other types of positions will follow a similar scale, with a basic college education bringing in the minimum, but the graduate degree holders coming out near the top.
That top might be the close to $90k. (The low end of the salary scale, alas, is $18k–which applies mostly to interns or worse.) Private industry salaries in the high five-figures may come with jobs like an on-call botanist gig that calls for crawling around worksites to check for building permit compliance, training work crews in how the environment works (assuming it does), and cooking up restoration plans. You'd think a job like that would come with hardship/casualty pay.
Not a chance.
But like all other modestly paid, overly credentialed workers, the option exists to make yourself an expert on something plantlike and peddle yourself as an expert—expert witness, expert speaker, expert on expertise—and hope that those speaking and consulting fees roll on in.