When we purchased our Littleton farm, in 1990, I discovered a healthy looking shrub beneath a pair of spruce trees east of the house. Never much of a botanist, I could not identify the shrub but noticed that its leaves, while softer and paler in color, resembled those of our locust trees. Small yellow flowers appeared by mid spring and, in mid summer, numerous small spindle-shaped pods hung from its branches, confirming that it is a legume.
Following years of failing to identify the shrub in field guides, the wonders of an internet search finally provided the answer; our lone, hardy shrub is a Siberian Pea Tree. Native to Siberia, China, Mongolia and Kazakistan, this deciduous shrub has been used for windbreaks across northern regions of the globe; while its seed pods may be cooked for human consumption, the abundant seeds are favored by a wide variety of birds and small mammals, including domestic chickens.
Though our Siberian Pea Tree has adapted well to the Front Range soil and climate (without artificial feeding or watering), it has not spread to other sites on the farm (unlike locusts, lilacs, wild cherries, wild plums and chokecherries); indeed, I have scattered its seed myself without success. Apparently, this hardy yet attractive shrub is a reluctant parent.