Tools
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Three tools, each answering one question from data you supply. The hardiness zone finder gives the USDA zone recorded for a ZIP code, from the 2023 map. The frost-date tool gives the dates by which a freeze at 32 degrees Fahrenheit had happened in 10, 50 and 90 per cent of the years on record at the weather stations nearest you, which is what a frost date actually is: a probability rather than a deadline. The plant finder filters the plants published here by the facts their pages already show - indoor and outdoor light, plant type, hardiness range, mature height, and whether a plant is recorded as toxic to cats or to dogs.
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All three run entirely in your browser, against static data files this site publishes. A ZIP code typed into one of them is never sent to us or to anyone else, nothing you enter is stored, and the tools keep working if your connection drops after the page has loaded. The zone finder reads the 2023 USDA map produced by the PRISM Climate Group at Oregon State University; the frost-date tool reads the NOAA 1991-2020 U.S. Climate Normals and names the station it used, along with how far that station is from you. The distance matters more than people expect, because cold air drains downhill and pools in hollows, so a low garden freezes earlier and later than a station on higher ground a few miles away. The plant finder searches only plants that carry a verified value for the fact you are filtering on, so a plant whose mature height no cited source states is absent from a height filter rather than guessed into a band. That is most important in the pet-safety filters, where an absent record means nothing has been documented and not that the plant is safe. None of these tools names a plant for you from a photograph, and none of them replaces the plant's own page, where every value carries its source and the date it was checked.