The map is based on a formula that takes into consideration several meteorological factors affecting the hardiness of a plant in a given location. The most important element in plant survival is the minimum temperature during the winter. Other important considerations are the length of the frost-free period, summer rainfall, maximum temperatures, snow cover and wind. I guess we here in Canada require this type of zone map more than you folks in the south. With increasing interest in container gardening, plant breeders and seed companies are working on vegetables specifically bred for container culture.
Planter boxes with trellises and extra colour for the area.
Container gardening presents opportunities for many innovative ideas. There is no limitation in the creativity of our design. I didn't think so after I had the pleasure of viewing their Flash presentation. The Sydney Opera House virtual tour. One of the best Flash sites I have seen folks.