Searching for the best choices if you need to cut down the tree maintenance costs? Start with picking the right trees for Colorado! Russian Hawthorns are one of the most drought-tolerant trees on our list. Again, establishing these trees with two seasons of normal watering will get their root systems healthy and strong enough to withstand dry conditions. Susan highly recommends Russian Hawthorn. It was the first tree she nominated for our list! Russian Hawthorns mature at 15 to 20 feet tall and wide with an upright oval form and slightly spreading lower branches. These hawthorns have beautiful, finely-cut, dark …