Plant care advice on the internet has a habit of being copied from one site to the next until nobody remembers where a number came from. We do it differently, and since the difference occasionally makes our numbers look more cautious than what you'll read elsewhere, this page explains why.
We research the plant, not the category
Every plant we list gets researched on its own: its native range, the elevation it actually grows at, and the care that follows from where it evolved. A cactus from a frosty Andean slope and a cactus from a warm coastal valley need different advice, even when they're cousins. So we never let one plant's care ride along onto another just because they look alike, and we write every care section fresh.
Climate facts get checked twice
The facts that can kill a plant in the wrong climate, cold hardiness above all, get cross-checked against at least two independent sources, ideally a botanical authority plus growers with real winters behind them. Names get the same care: we verify every botanical name against Kew's Plants of the World Online, and where botanists genuinely disagree, we say so on the page instead of pretending the argument is settled.
When sources disagree, we publish the cautious number
This is the part that makes us look conservative. If one source says a plant takes 15 F and another says 25 F, we publish the safer end, on purpose. Understating hardiness costs you a little extra winter protection. Overstating it costs you the plant. We'd rather you be pleasantly surprised than shopping for a replacement, and where we have our own overwintering experience here in Riverside County, we upgrade a number once our plants have earned it.
If you ever think we've gotten a fact wrong, email us at support@thoughtfulpricks.com. We keep a record of every fact and the source behind it, and we'd rather correct a page than defend it.