Performance of oaks, both existing and test-planted, as determined by former Apple Senior Arborist Dave Muffly. Please see www.oaktopia.org for more information on and photographs of many of the trees listed below.
Superior Performance
Quercus agrifolia – the most common native tree by far, but narrowly adapted endemic species vulnerable to climate disruption
Q. castaneifolia – potent, large oaks that need to be selected for growth habit and clean winter leaf drop
Q. cerris – selected for aphid-resistant taxa and clean winter leaf drop
Q. engelmannii – consistent performance of species and taxa, moderate size, generally upright growth, climate change adaptive replacement for both Q. agrifolia and locally-faltering Q. douglasii
Q. lobata – must be nursery selected for powdery mildew resistance and growth habit in nursery
Q. macrocarpa – close relative to Q. lobata, must be selected for powdery mildew resistance, bewildering array of taxa
Q. trojana – smaller, highly drought resistant oak with upright growth habit, but can make large acorns
Good Performance
Quercus calliprinos – handles harshest conditions, viciously spiny leaves, shrubby growth, pure form requires excellent soil drainage
Q. canbyi – promising moderate size oak with attractive winter color, not for harsh sites
Q. gambelii – closest natural relative to Q. lobata but smaller, must be selected for powdery mildew resistance
Q. shumardii – must be selected in nursery for clean winter leaf drop, oversize basal flare
Q. polymorpha – late fall new growth often killed by low temperatures, variable winter leaf drop
Adequate Performance
Quercus nigra – variable chlorosis resistance, weak branch attachments, slow growth, lack of drought resistance
Q. coccinea – hold dead leaves in winter until maturity, oversize basal flare, lack of drought resistance
Variable Performance
Quercus ithaburensis – true Q. ithaburensis is a solid performer, but most available seed is hybridized and variable
Q. lobata – staggering variability in powdery mildew resistance and growth habit, with good trees fantastic and bad ones tragic
Compromised Performance
Quercus robur – sooty mold on all specimens observed throughout Bay Area
Q. robur ‘Fastigiata’ – controversial growth habit, hold dead leaves in winter
Q. ×sargentii – hybrid with Q. robur. Good growth but consistent sooty mold
Q. douglasii – incessant powdery mildew, highly compromised growth, natural seedlings rare
Q. kelloggii – exhibit a wide variety of leaf diseases when grown outside native range
Q. chrysolepsis – not a survivor species on valley floor – all historical specimens planted died young
Q. palustris – prone to severe chlorosis, hold dead leaves in winter, typically very short-lived
Q. turbinella hybrids – prone to severe powdery mildew
Responses