No, olive trees will be significantly damaged when the temperature is below 14 degrees F (-10 degrees C)
This corresponds to USDA Zone 8.
Sources:
http://en.wikipedia.org/wiki/Olive
http://www.usna.usda.gov/Hardzone/ushzmap.html
Kiwi will grow entirely successfully outdoors in the UK (USDA zone 8-9)
Potatoes can be grown anywhere that has a USDA zone 3 of above.
There are many fruit trees that grow in zone 7. Some include; apple, pear, peach, plum and even cherry.
It does grow in Windsor and Niagara .. . Zone 6
Why do different perspectives exist
Above the timber line is the alpine zone. This zone is an area in which trees cannot grow because the altitude makes it too cold for the trees to survive.
The parts of Wisconsin that are zone 5 could grow the Chicago Hardy Fig.
The climate zone for Kentucky ranges from USDA Zone 5b to USDA Zone 6b. These zones help to determine when to plant certain crops during specific times of the year.
Because of there precipitation.
Cherry Blossom trees can grow in zones from 5 to 8
Ought to work. Ginkgo's are zone 5 trees. I've seen them in northern Indiana; Tampa shouldn't be a problem. See the USDA's site for tree hardiness. I see them in Kissimmee(zone 9)
Propagated by seeds or division, Iris domestica (blackberry lily, leopard lily, leopard flower) is hardy to USDA plant hardiness zone 5.