The Ironwood is a desert native tree for lower elevations, so this species is suitable only for those parts of Tucson that are in warm pockets. This tree is not hardy in elevations above 2500 feet, which includes the Green Valley area.
This lovely tree is very slow-growing, and mostly evergreen unless temperatures dip well below freezing. Like many native plants, the Ironwood will drop its leaves when drought stressed, too.
The lovely gray bark compliments the green leaves, but the flower show is what makes this a dramatic tree for your landscaping. In the spring, pea-shaped pinkish to purple flowers appear, followed by hairy bean pods.
If you have Ironwoods growing naturally around your home, this means you may have good luck growing citrus. The Ironwood and Sahuaro species are both called “indicator” plants; meaning they indicate the climate may be suitable for citrus. There are, of course, exceptions to this rule, as the hard freeze of February 2011 in the Tucson area zapped all citrus trees hard no matter where they were planted.
Reference: Mountain States Wholesale Nursery and Gregg Starr Nursery Plant Info Sheet, 1999.