Desert ironwood (Olneya tesota), or patio Fierro as it is known in Mexico, is a special tree found naturally growing only in the Sonoran Desert of Arizona, Sonora, and Baja California. This slow growing evergreen tree may live for up to 800 years if not harvested for tourist wood carvings, "mesquite charcoal", or if not cleared from grazing land.

In the wild, the ironwood is especially valuable. Its roots stabilize wash banks, and since it is a legume, it provides nitrogen for surrounding foliage. The ironwood is one of the desert's "nurse plants". It provides shady, sheltered area for more fragile plants such as the cereus and acuna cacti and the Tumamoc globe-berry. So, as the desert ironwood disappears, so other species will follow.

Desert animals also need the ironwood. It is a shelter for quail, javelina, deer, and migrating birds. Its seeds are edible and taste somewhat like peanuts.

In desert landscaping the ironwood is also a valuable tree. It is not for cold desert areas, as its foliage will be damaged when the temperatures go down to the low 20's. But elsewhere its' tiny, mesquite-like gray-green evergreen leaves provide dense shade. In the spring, it produces many pea-like lavender flowers, but seems to have non-allergenic pollen. Its sharp thorns require that the tree be pruned above head height, and be planted away from walkways. It is easily transplanted and doesn't need water if it is planted in deep soil. The ironwood will grow at a moderate rate if it is irrigated along with the other garden plants.