USDA Growing Zones:
Average Daily Temperatures by Zip Code: http://www.ncdc.noaa.gov/oa/dataaccesstools.html#climate
Hostas can survive in Zone 9. They thrive through Zone 8.
- Hostas need to lose their leaves and go into dormancy each year. They need a temperature of under 43 degrees Fahrenheit for a period of 30 days although longer and colder is better. If orange trees grow in your area, hostas will not do well there! Hosta growing zones are not guaranteed to support all varieties.
- The best hosta growing results in the south will come from hostas with ancestry of H. plantaginea, a tropical plant which evolved in a warmer climate in eastern China. This hosta is the most fragrant and the only fragrant hosta of the 20 to 40 original species. Keep H. plantaginea hostas and its offspring (listed below) well-watered, especially in the south. Most of these fragrant varieties will tolerate more sun than other hostas. Do not fertilize when it is hot outside.
- Hostas evolved primarily in Japan but also in eastern China and South Korea. The hosta species evolving in the warmest climates include H. clausa, H. gracillima, H. kikutii, H. longipes, H. montana (southern forms), H. nakaiana, H. plantaginea, H. rupifraga, H. ventricosa, H. venusta, and H. yingeri.