You might take a look at the Colorado forums on City Data: http://www.city-data.com/forum/colorado/. There are lots of posts to read and you can start your own thread with the questions you'd like answered. Good luck! I moved from Dallas (Plano actually) 25 years ago and love it here!!

It is looking like the chocolate mint is coming on, so should be able to get some starts from that and the sage is showing green. Are you going to the spring swap? I am about an hour north of the metro but could bring starts to the swap. How about horseradish? Not sure if rhubarb is an herb?

Check out the thread linked below. It's a few years old but Timberline Gardens linked in that thread is still probably your best bet for information in Denver! Skybird Here is a link that might be useful: Joshua Tree Yucca thread!

May I suggest you look at Colorado Springs (if that is an option). I lived there for 12 years, it is growing and thriving but is not as busy, over crowded or expensive as the Denver area. Castle Rock is also a great option and close to Denver. The polution (inversion) in Denver is really getting bad too.