Tree Blog

Quercus virginiana | Arcadia

There is another good, if unfortunate, reason for Southern Live Oak (Quercus virginiana) to be used in coastal California. For decades, California has relied on container-grown tree stock, with disastrous results. It is very difficult to grow container trees absent substantial levels of root circling and girdling. Girdling and circling roots occur beneath the soil surface, and take effort to discern during inspection. These inspections became rare, and a race for the bottom ensued, with trees grown at low prices which could never perform in the landscape. Certain trees have proven more tolerant of these miserable growing techniques, through root grafting. Unfortunately for California, drought-adapted trees are typically poor for root grafting, and simply become stunted and diseased. Water loving trees are more likely to root graft, so those trees grew better than their drought adapted counterparts, leading to further maladaptive emphasis on water loving tree species in a state whose climate is defined by drought. Southern Live Oak, with a drought adaptation approaching that of native California Valley Oak (Q. lobata), also has extraordinary root grafting capability, as shown here in a photo of a mature Southern Live Oak in Arcadia.

Dave Muffly