as to a question about whether Roger's Red cultivar of the wild California grape will grow in Zone 5, here's what I found at the Jepson Horticultural Database, a most useful project of the University of California's Jepson Herbarium:
Information from the Jepson Horticultural Database for Vitis californica
Given no specific additional requirements, grows especially well in zone 6 and also in zones 4 and 5.
Given moderate summer watering, grows especially well in zones 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, and 24 and also in zones 7, 8, 9, 10, 11, and 12.
Cultivars available in the horticultural trade.
Hmmm... as I'm writing this I realize there is a zone identification problem. The zones referred to in the Jepson Manual are based on the Sunset Magazine gardening zones of which there are 24 that apply only to Pacific coast and western U.S. areas. (And Sunset Magazine does not allow on-line access to it's zone index unless you subscribe to the mag.) In this system, Zone 5 is represented by coastal Oregon. The USDA climate zone system is a "plant hardiness" index based on temperature gradients and applies to the entire U.S. In this system Zone 5 is an area that can experience temperatures in the lower ranges from -10 degrees to -20 degrees.
Now I think I need to investigate how far up into the mountains the California grape will grow which may give me an idea of how cold hardy it is. There's no easy answer to the original question....
Posted by briggs at December 14, 2004 2:34 PM | TrackBack