Tree
Southern live oak
Quercus virginiana · Fagaceae
Also called: Live oak, Coastal live oak, Heritage live oak
Southern live oak (Quercus virginiana) is a moderate-water tree well suited to Tucson and the low desert. It thrives in full sun.
Southern live oak at a glance
- Water use
- Moderate (established)
- Sun
- Full sun.
- Mature size
- Typically 30-50 ft tall and 40-60+ ft wide in landscape settings; massive, low-branching, spreading evergreen canopy.
- Growth rate
- Moderate (fairly rapid when young, slowing with age; faster than most oaks)
- Bloom
- Inconspicuous (yellow-green catkins), Inconspicuous catkins in spring, followed by acorns in fall.
- Cold hardiness
- Evergreen and very cold hardy; fully hardy in Tucson with no frost protection needed.
- Soil
- Adapts to a wide range of desert soils including alkaline and clay; tolerates caliche and benefits from deep, well-distributed irrigation in well-drained soil.
- Native range
- Native to the southeastern U.S. coastal plain (Virginia to Texas); not native to Arizona but well adapted to Tucson.
- Best used as
- Large evergreen shade tree, Specimen / heritage tree, Street and park tree, Long-lived legacy plantings
- Wildlife
- High value: acorns feed birds and mammals; dense evergreen canopy provides nesting and cover. Supports many insects and pollinators.
- Toxicity
- Acorns and young foliage contain tannins that are toxic to livestock (cattle, horses) in quantity and can cause stomach upset in dogs; generally low risk to people. Flag for pets/livestock that may chew acorns.
How to grow Southern live oak in Tucson & the low desert
Watering
Tolerates more soil moisture than most desert trees; responds well to deep drip irrigation in Tucson. Water deeply and widely (out to the dripline) about every 7-14 days in summer and monthly or less in winter once established; accepts periodic drought once mature but grows best with regular deep watering.
Fertilizer & nutrients
Low to moderate needs. Apply a balanced or slow-release tree fertilizer in spring if growth lags. Watch for iron/manganese chlorosis in high-pH desert soils and treat with chelated iron or soil sulfur as needed.
Pruning & care
Prune young trees in winter to establish a strong central leader and well-spaced scaffold limbs; raise the canopy gradually. Mature trees need only light corrective pruning. Avoid heavy cuts that invite decay.
Notes
A premier large evergreen shade and legacy tree for Tucson, popular in parks and larger landscapes; the locally selected 'Joan Lionetti' is a well-adapted, drought-hardy form. Needs ample root space and deep irrigation; not for small lots. Watch for chlorosis in high-pH soils.
Sources: Arid Zone Trees - Quercus virginiana; Tucson Clean & Beautiful / Civano (Joan Lionetti live oak); University of Arizona Cooperative Extension; Pima County Master Gardeners