I noticed I went from 8a to 7b. I used to be 7b for a long time and then it changed to the warmer zone 8a some time back. The problem is whether it's the same zone map or if the one that I used that changed it to 8a was from another source, and not a USDA map. It might not matter in my case anyway. I'm going to be really close to that line going to Laredo and may be in the area where it says the map doesn't work well. But I know that already, no matter which side of the line I'm on. Lots of experience with the assigned zone not working for me.
