As noted above, garden epimediums are mostly from Europe (and a few from Japan), though a number of Chinese species have recently become more widely available. The European species are usually considered the most drought-tolerant, as are many hybrids of Asian and European species. The newer Chinese epimediums aren’t necessarily less drought-tolerant, but they’re a bit of an unknown quantity, as many have not been studied as thoroughly as the older European and Japanese varieties.