While it is true that Jane's "try everything" is the ultimate test of perenniality (sorry if that word does not yet exist!) I do think that "Fierycloud" has a valid point. There is no data base that I know of to cover even the climate (really, it's the temperature) limits for many bulbs. Sure, there is information put out by well-known growers for species of tulips and daffodils, with far more limited bases for their hybrids and there are some to help people for a few other genera. There's much work to be done in establishing a data base for a wide range of genera. Many would find it useful especially if other climatic factors such as the presence or absence of summer rain were included in a systematic way. Going beyond that, to include soil conditions and pests, as Jane suggests, is unlikely to be accomplished except in a qualitative manner. That's where personal intuition and general experience counts. Of course, that's why many of us grow bulbs, to find out what, where and how to grow them. Andrew Wilson San Diego "Fierycloud" in Taiwan wrote: >I always have a question that which commercial available varieties and species would perennialize in which climate zone, but I just can't find a comprehensive information. Only some web-shop would marked some of their bulbs as vigor, perennializing and naturalizing for the location where the shops are. Jane McGary wrote: I think it's not possible to predict this based only on climate. Many other factors affect how a bulbous plant can perennialize in one spot or another, including drainage, and especially the presence of predators and diseases. For example, some people in my own area say they cannot grow Narcissus because they always die. This may be caused by bulb fly, or perhaps by bad drainage. ..... In summary, it would be difficult for me to say what bulbs, other than Colchicum, "perennialize" in my own area, and it would be even more difficult for vendors to say, because most of them offer stock that's grown under very artificial conditions and never allowed to perennialize. The only advice I can offer is one of the best pieces of advice ever given to me: "Try everything."