By Kirstee Schutte, Nebraska Extension Master Gardener
In 1930, President Hoover signed the Plant Patent Act into law. For a plant to be patentable, it must be cultivated and capable of asexual propagation. Some plants are sold with labels that include a patent number or a phrase such as “Propagation Prohibited” or “Plant Patent Applied For (PPAF).” The United States Patent and Trademark Office (USPTO) grants plant patents for a nonrenewable period of twenty years starting from the date an inventor files the patent application.