Does it matter that much?
Where do I find out what "zone" I am in ?
It does. There are a lot of things that can't handle too much cold or heat. Where is Montgomery? Most of Texas is 7 or 8 unless you're way north or right along the coast. If you want to see for sure, Google USDA Plant Hardiness map. Also remember that when things say they can take full sun, they don't always mean Texas sun.
I checked, your 8b. That means the warmer half of zone 8. Things like plumbago and purple fountain grass are perennials for you, but annuals for me. It also means that you an probably gorw things like lettuce and spinach all winter long, I can't. Hope that helps.
Google Gardening zone and you would have your answer.
So I go to the link BLKS posted and it says I'm in zone 8A. I go to GardenWeb.com and I'm in zone 9. I go to USNA-USDA website and I'm on the cusp between 8b and 9a.
So how do I know?
Arizona has all kinds of mini climates due to desert and mountains. This is the most recent available and shows the flow of microclimates in your area.
That is an excellent link, themoonhowl. Hadn't seen that one before. Thank you.
You are welcome BLKS. I like that one too. It is a bit more detailed than most.
Keep in mind the zones are guidelines. The plants don't know where the exact boundaries are, hee hee.
Yes, that is true, shune. There can be microclimates within the yard even.