Answer: The Oriental lily 'Casa Blanca' is hardy in all USDA zones. Lilium require excellent drainage and a pH of 5.5 to 6. These bulbs are available from Dutch Bulbs, 1-800-622-9997.
You can glean lots of information from the Dutch Bulb website at http://catalog.dutchbulbs.com/index.html
They even have books available!
Lily-of-the-Valley is Convallaria majalis, a member of the lily family, but does not resemble the Oriental lily 'Casa Blanca'.
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