Quercus douglasii

Identification

Description

A deciduous oak tree, usually growing to 30 feet, although this oak can sometimes can go to 50 ft. Blue oak has blue-green leaves and light-colored bark.. A California native from Los Angeles to Sacramento. This is not a fast tree and would be a candidate for bonsai. Blue oak is associated with Rhamnus calif., Ceanothus cuneatus, Ceanothus leucodermis, Arctostaphylos glauca, Arctostaphylos viscida, Aesculus calif., Quercus lobata, Quercus agrifolia, Quercus wis., Cercocarpus betuloides , etc. (A native oak on the Santa Margarita nursery site.) Blue oak has done well here with little care and no water. We have dumped out the bad acorns and had them all grow! Easy but very slow, 1-3 inches/year, with occasional bursts of moderate, 1 FOOT. The leaf is blue-grey with no bristles and little or no lobes. (There are hybrids throughout the stands that have bristles, lobes and hair everywhere, so do not get confused if your blue oak stand is not pure.) The 'Spanish Moss', Ramalina menziesii, that commonly grows on blue oaks lives on moist air, the tree is just a way for it to be high in the air. The tree recoops it's burden by having increased moisture drip and fertility from the epiphytic lichen. (Knops, Nash and Schlesinger, 1996) Do not worry about the moss unless it gets bigger than the tree, then you can mechanically pull it out and back into balance. We used to think that Quercus Douglasii and some of the other interior California oaks did not require nor create a litter layer of their own. That has proven to be wrong. The interior oaks cannot build a litter layer unless they are totally weed free. If any weeds are under their canopy the leaf accumulation will be less than the leaf drop. The live oaks actually drop a higher volume of leaves and can slowly build a litter layer with just a little help. The interior forms need much longer, sometimes decades. Ecology is easy to mess with, slow and hard to fix. Oaks.