Pronounciation: QUER-cus foo-sa-FOR-mis

Hardiness zones
Sunset 12-24
USDA 7-11

Landscape Use: This is a moderately large, spreading evergreen shade white oak tree for both xeric, oasis, and mesic landscape designs. In Phoenix, this is a great tree to complement Mediterranean or Spanish architectural styles. In Phoenix, this is NOT a street tree or a parking lot tree (unless one likes burnt french fries).

Form & Character: Texas live oak is wide spreading and has a strong, stately, rugged character, spiritual, permanent.

Growth Habit: Evergreen, woody, broadleaf perennial tree, slow to moderate growth rate when young to moderate with age to 40-feet tall with greater spread. Texas live oak has a wide range of growth habits that are related to cline. They can range from relatively small and shrubby to large, stately and spreading. Nursery-grown selections are generally always upright and spreading. Overall, Texas live oak is a long-lived, nearly evergreen tree that especially when young is prone to grow epicormic shoots or suckers from its roots or trunk base. Evergreen Texas live oak trees will actually senesce older foliage (turn orange and fall off) in March at the same time new foliage for the upcoming growing season is produced.

Foliage/Texture: Leaves are alternate, elliptic to oblong sometimes with lobes and/or dentate margins, otherwise entire and smooth to 5 inches long maximum, dark green above, heavily tomentose underneath; medium coarse texture.

Flowers & Fruits: Oaks are monoecious, males flowers catkin like and drooping, female flowers in one to many flowered spikes; fruit is an acorn, cup encloses about 25% of nut (seed). Live oak seeds are disseminated by gravity.

Seasonal Color: None, though new foliar growth in early spring is a bright, light green.

Temperature: Tolerant of desert heat and cold, except when planted as a street or parking lot tree surrounded by copious impervious sufaces (concrete and asphalt).

Light: Full sun, though younger trees are HIGHLY susceptible to western trunk sunscld injury if their crowns are raised too high to create that "lolly pop" young tree look.

Soil: Tolerant of most desert urban conditions, extremely salt tolerant.

Watering: Texas live oak (especially those selected from its western range of Texas and north Mexico) are moderately drought tolerant (even by desert standards) and are quite adaptable with proper placement to a range of mesic, oasis, and even xeric landscape design settings.

Pruning: Elevate canopy base only as needed, eliminate root suckers, and please resist crown thinning or excessive crown raising especially when trees are young and developing.

Unintended consequences: As noted, Texas live oak trees (most notably when young) tend to grow epicormic shoots at their base (basal suckers). Additionally, young Texas live oak trees are quite prone to severe trunk sunscald injury if miscast as a street or parking lot tree and "lolly pop" pruned to simulate a young "mature-looking" tree. The outcome of this calamity of landscape choices and miscare usually results in the mortality of young trees, but this can sometimes end up going in a completely different direction. For example, check out this Texas live oak landscape table.

Propagation: Sexually by seed or asexually by cuttings using basal or epicormal shoots.

Disease and Pests: Spider mites are most common problem. Other lesser problems include aphids (during early spring), oak root rot fungus, oak wilt fungus, and Texas root rot, and galls.

Additional comments: Texas live oak is a great and popular evergreen tree for many landscape situations in Phoenix (except where already noted). Though large at maturity, it is quite slow growing and is HIGHLY susceptible to trunk sunscald if miscast in the wrong location in a landscape (e.g. surrounded by impervious surfaces).

Although the current accepted scientific name of Texas live oak is Quercus fusiformis, there is no full consensus among taxonomist concerning the taxonomic status of Texas live oak. Some still consider it to be a varietal cline of Quercus virginiana (called variety fusiformis). Moreover, to add to the name confusion in central Texas, Quercus fusiformis is known to readily hybridize with Quercus virginiana. One thing we do know for sure is that Texas live oak is dense wooded and will buckle concrete.

Historical notes: Quercus are concentrated in the northern hemisphere and number about 600 species. Quercus belongs to a genus steeped in the prehistory of Europe, and were well known to Linnaeus who first named them Quercus. Oaks were venerated by ancient tree-worshipping tribes. Very large, old oak trees were often worshipped because these tribal peoples thought that they embodied powerful spirits that could foretell the future. Live oaks (evergreen oaks) are considered one of the noblest trees in the world and are virtually an emblem of the 'Old South' United States.

Consider the following written by Dr. Oliver Wendell Holmes: "There is a mother-idea in each particular kind of tree, which, if well marked, is probably embodied in the poetry of every language. Take the Oak, for instance, and we find it always standing as a type of strength and endurance. I wonder if you ever thought of the single mark of supremacy which distinguishes this tree from all our other forest trees? All the rest of them shirk the work of resisting gravity: the Oak alone defies it. It chooses the horizontal direction for its limbs, so that their whole weight may tell, and then stretches them out fifty or sixty feet, so that the strain may be mighty enough to be worth resisting. You will find that, in passing from the extreme downward droop of the branches of the weeping willow to the extreme upward inclination of those of the poplar, they sweep nearly half a circle. At ninety degrees the Oak stops short: to slant upward another degree would mark infirmity of purpose: to bend downwards, weakness of organisation."