Answer: In most cases it is a real risk to try to grow a plant in just one zone colder than that for which it is rated. If you have a particularly sheltered location with excellent wind breaks, perhaps living in town and with heat reflected from a building or even up against a foundation, and are able to mulch heavily, the plant might survive. Hardiness also seems to increase a little bit once a plant is well established, so in some cases a borderline hardy plant will make it if the first winter is milder than usual. To attempt to cross two zones is usually futile. So, unfortunately, I am not very encouraging although if you are willing to take a risk it is sometimes worth the effort. You might want to talk to your county extension (788-4961) and see which varieties they specifically recommend for your area.
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