Quercus engelmanii x castaneifolia | Visalia
Returning to urban environs, we now look at downtown Visalia. Brian Kempf and the Urban Tree Foundation experimented with many kinds of trees during their years in Visalia, including these “Engelman Oaks” in street tree cutouts. These trees came from Calaveras Nursery in Valley Springs, California, by Mick and Pat Stockard. Acorns were collected from the Shields Oak Grove in Davis. Upon close observation, it's clear that these well-pruned specimens were not true-to-species Engelman Oak, but in fact, are hybridized. Experience in growing seedlings from the Shields Grove Engelman Oaks, suggests primary introgression from Q. macrocarpa, Q. muehlenbergii, and, perhaps surprisingly, Q. castaneifolia.