Here's how it works. When you purchase plants, they will often have an indication of their hardiness zones. This means you plant will have the best success if you live in the zones indicated. You can see some examples from some packages by clicking here. The higher the number, the warmer the zone - zone 7 is much warmer, on average, than zone 4.
However, even if you don't live in the zones indicated, you may still be able to be successful in growing your plants. In general, plants will still thrive if they are within about three colder zones. Here are a couple of examples:
- You buy a plant that has a recommended zone of 6. If you live in any zone from 6 to 3, the plant can survive.
- You buy a plant that has a recommended zone of 6. You live in zone 7. This plant may not survive your winter. If you want to grow this plant, you will be best to dig it up in the fall and store it indoors.
- You buy a plant recommended for zone 3a. You live in zone 7. This plant is not likely to survive - not because it is too cold, but rather, because it will be too hot for the plant.