Explorer Thomas Mitchell collected the type specimen, from which George Bentham wrote the species description in 1842. No subspecies are recognised. The bark of "A. pycnantha" produces more tannin than any other wattle species, resulting in its commercial cultivation for production of this compound. It has been widely grown as an ornamental garden plant and for cut flower production, but has become a weed in South Africa, Tanzania, Italy, Portugal, Sardinia, India, Indonesia, New Zealand, as well as Western Australia, Tasmania and New South Wales. "Acacia pycnantha" was made the official floral emblem of Australia in 1988, and has been featured on the country's postal stamps.