I live in Texas. EVERYONE wears boots xD Jeans are usually tucked in if you wear skinny jeans, to show off the tops, or over if you wear bootcut jeans.
I always tuck my Redhead boots in though. Doesn't matter what kind of boots I'm wearing. I'd rather get my weatherpoof old boots covered in manure and mud than my jeans! They're big and clunky and probably look funny, but they're comfortable and I do a LOT of walking, so I really don't give a rats patootie what people think. I usually have an old, horse-snotty shirt on too xD
I tuck my jeans into my fitted farm rain boots too. No use wearing rain boots if you're going to get your jeans wet, and we always have a flooded water trough or two that makes a mud pit for the horses to stand in the middle of when you're trying to catch them! Plus, those boots against my calves gives me a rash ._.