Hi! For Christmas, try using cactus as your 'tree' theme, and sparkle on it for the festive look. You can do this for any size real or faux cactus. Also, for your Christmas lights, there are lots out there with the 'southwest' look, such as bright red chili peppers or cactus. Often times these can be found for summer parties, so you may find some on clearance this time of year. I lived in the California desert for 10 years, and one of the most creative lawn displays I saw was snowmen tumbleweeds! Three tumblweeds stacked up like a snowman, spray-painted white! It was a cute and whimsical way to use natural materials to celebrate Christmas in the desert! (not to mention affordable, if you have an abundance of tumbleweeds!) You could also attach the white sparkle lights to them. As for Fall. the southwest is blessed naturally with browns, oranges, pinks, and reds. How about a fall display of gourds, corn, and leaves spread on a brightly clored Native-American style placemat or blanket throw? Have fun! Hope that helps!