Chokecherries are ripening on Colorado slopes from August through September.
Their deep purple color at this time of year contrasts with the bright red of early spring.
In this audio-postcard, Boulder naturalist Stephen R. Jones, author of the new book, Nourishing Waters, Comforting Sky, and co-author of Butterflies of the Colorado Front Range, explores the chokecherry crop on Boulder's open space.
Summer monsoon rains have created a bumper crop of chokecherries this year.
Chokecherries are a favorite of the region's native tribes, including the Arapaho, Cheyenne, Mountain Utes, and Lakota (canpa’-hu.)
While they are growing sweeter at this time of year, these berries are very astringent for much of the summer, giving the reason for their name.