About this site

A US plant patent runs about twenty years from its filing date, after which the cultivar is public domain — anyone may propagate and sell it. Plant patents carry no maintenance fees, so unlike other patents they cannot lapse early. That makes each expiration date fixed and knowable from the public record — though not, as the next section explains, a simple sum.

Other people publish these dates, and the good ones handle patent term adjustment — the extension a patent earns when the Patent Office itself causes delay. That covers about a quarter of all plant patents, and it is the larger share of the problem.

What tends to get left out is the other direction. A terminal disclaimer gives term back, so the patent ends earlier than filing plus twenty years — and a source that skips it tells you a plant is still protected when it is already free. In this corpus 445 patents end early for that reason, by a median of two years and in one case by nearly seven. Those dates are taken from the patent rather than calculated, so they are right here.

Where the data comes from

The patent records come from the USPTO public record via the Google Patents public dataset. Expiration dates are taken from that record rather than worked out here — and we say, on every patent, which of two things the date is.

For about a quarter of plant patents, a term adjustment or a terminal disclaimer appears on the face of the patent. Those dates are not filing plus twenty years and could not be arrived at by arithmetic. For the rest, no adjustment is recorded, and the date is the full statutory term from the filing date.

We draw that distinction rather than calling every date “official”, because the site’s only asset is being accurate about what it knows.

That distinction matters more than it sounds. Naive arithmetic — filing date plus twenty years — disagrees with the official date on more than a quarter of all plant patents, by as much as six years in either direction. Patent term adjustment extends some; terminal disclaimers and inherited parent filing dates shorten others. Publishing the arithmetic would have been wrong for thousands of plants.

What is covered, and what is not

This site holds every US plant patent granted from 1977 onward — about 33,400 of them, complete through the most recent weekly grant. Coverage is continuous: the handful of patent numbers with no page here were never issued, usually applications withdrawn before grant.

Plant patents granted before 1977 — roughly the first four thousand, from 1931 to 1976 — are deliberately left out. Every one of them expired decades ago, so the question this site exists to answer is already settled for them: they are in the public domain, and anyone may propagate and sell them freely. Including them would have added four thousand pages whose answer is always the same.

That era is also where the record itself thins out. Naming a new plant was not yet standard practice: a breeder would patent a cultivar without giving it a name at all, and the grant identified it by number, parentage and a written description of the flower and foliage instead. Roughly three in four patents from the 1930s carry no cultivar name, and more than half of those from the 1970s. The proportion falls through the 1980s, and by the mid-1990s — once plants began to be marketed under brand names — nearly every patent names its plant. Where a patent of any era does name one, we show it; where it does not, we say so rather than inventing one.

Why we can reproduce the patents

The abstract and claim on each page are quoted word for word, and the photograph is the one printed in the patent. Both are reproduced on the USPTO’s own stated position: “Patents are published as part of the terms of granting the patent to the inventor. Subject to limited exceptions reflected in 37 CFR 1.71(d) & (e) and 1.84(s), the text and drawings of a patent are typically not subject to copyright restrictions.”

Where an applicant does claim copyright in their patent, 37 CFR 1.71(e) requires them to license alongside it “facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records”. A copyright notice is therefore the clearer case, not the riskier one, and where a patent carries one it is shown beside the figure.

That phrase — as it appears — is why nothing here is altered. Photographs are resized to fit the page and never cropped, retouched or used as decoration; abstracts and claims are quoted in full rather than trimmed or reworded; and every one is captioned with the patent it came from. This is a reference to the public record, not a picture library.

How the dates were checked

Beyond internal consistency checks, a sample of patents was verified against the scanned grant document itself — the printed front page states its own term adjustment, which makes the expiration date recomputable from the original paper rather than from any database field. Where both could be read, they agreed.

What this site does not tell you

A patent expiring frees the plant, not the name. Trademarks renew indefinitely. Knock Out® remains a live trademark long after the patent on the rose expired; the plant itself is sold as Rosa ‘Radrazz’. Before selling under any brand name, check the trademark separately.

Some patents record no cultivar name at all. Where that is true the site says so rather than guessing — mostly pre-1970s patents, which identified a plant only by its number.

This is a reference site, not legal advice.