October 30, 2022 by mgnvmmfQuercus_phellos_Leaves_Acorns_Sep_CRW Maturing Quercus phellos (willow oak) acorns turn from green to brown between August and October. Photo © Christa Watters About mgnvmmf Previous Post:Quercus_phellos_Leaves_Acorns_Sep_CRW