The sprawling, moss-clad branches of a live oak, Quercus virginiana, make a dramatic and very picturesque statement. It’s one of the longest-lived oak trees and there is no doubt that a mature, centuries-old live oak has a theatrical quality.
I. Appearance and Characteristics
Quercus virginiana, also known as the southern live oak, is an evergreen oak tree endemic to the Southeastern United States. Though many other species are loosely called live oak, the southern live oak is particularly iconic of the Old South. Many very large and old specimens of live oak can be found today in the Deep South region of the United States.
Although live oaks retain their leaves nearly year-round, they are not true evergreens. Live oaks drop their leaves immediately before new leaves emerge in the spring. Occasionally, senescing leaves may turn yellow or contain brown spots in the winter, leading to the mistaken belief that the tree has oak wilt, whose symptoms typically occur in the summer. A live oak’s defoliation may occur sooner in marginal climates or in dry or cold winters.
The bark is dark, thick, and furrowed longitudinally. The leaves are stiff and leathery, with the tops shiny dark green and the bottoms pale gray and very tightly tomentose, simple and typically flattish with bony-opaque margins, with a length of 2–15 centimetres (3⁄4–6 inches) and a width of 1–5 cm (3⁄8–2 in), borne alternately. The male flowers are green hanging catkins with lengths of 7.5–10 cm (3–4 in). The acorns are small, 1–2.5 cm (3⁄8–1 in), oblong in shape (ovoid or oblong-ellipsoid), shiny and tan-brown to nearly black, often black at the tips, and borne singly or in clusters.
Depending on the growing conditions, live oaks vary from a shrub-size to large and spreading tree-size: typical open-grown trees reach 20 m (66 ft) in height, with a limb spread of nearly 27 m (89 ft). Their lower limbs often sweep down towards the ground before curving up again. They can grow at severe angles; Native Americans used to bend saplings over so that they would grow at extreme angles, to serve as trail markers.
The southern live oak has a deep taproot that anchors it when young and eventually develops into an extensive and widespread root system. This, along with its low center of gravity and other factors, makes the southern live oak extremely resistant to strong sustained winds, such as those seen in hurricanes.
Southern live oak is cultivated in warmer climates as a specimen tree or for shade in the southern United States (zone 8 and south), Nuevo León and Tamaulipas states in Mexico, and in the warmer parts of the United States, Europe, and Australia. Cultivation is relatively simple, as southern live oak seedlings grow fast with ample soil moisture. Planting depth has little effect on the success of the tree. After a few years live oak needs only occasional supplemental water. Southern live oak is very long lived, and there are many specimens that are more than 400 years old in the deep southern United States. The southern live oak is reliably hardy to USDA Hardiness Zone 8a, which places its northern limit for long-term cultivation inland around Atlanta and Memphis.
II. How to Grow and Care
Sunlight
Live oak should be planted in a field with full sun. It gives shade, shady plants can be planted under it.
Temperature
Live oak grows in a large range of temperatures. It is adaptable in hardiness zones 5-9.It prefers well drained soil with adequate ventilation in the tree canopy. Live oak will not do well in standing water. Also, leaf molds pose serious threats if the leaves cannot dry out in the wind. So make sure they are not stuck against buildings where rainwater may drain.
Watering
Keep soil moist but well drained. Oaks form a taproot and will draw moisture up from below. So make sure there is humid soil if you dig down a few inches, but do not flood the topsoil. Reducing summer water will make live oak more healthy, they tolerate summer dry spells very well.
Soil
Ideal soils are well-drained loam, sandy-loam, or sandy-clay soils. Some alluvial fan areas and silts harbor good oaks stands. The key in all of these is that the soil is well-drained. Standing water cannot be tolerated by oaks.
Fertilizing
Live oak can survive and thrive without supplemental fertilization. But if you wish to give them extra nutrients you can add some of 12-6-6 (N-P-K) fertilizer. This has more of a ratio of nitrogen than phosphorus and potassium. Also, consider the natural environment of oaks. They grow where there is lots of forest litter. This forest litter acts as natural mulch that breaks down into organic matter and humus. So one way to give some natural nutrition is to spread mulch by your oak trees. They will love the extra organic matter.
Planting Instructions
It may take a very long time if you want to get a mature oak tree from an acorn. But with patience, planting a small tree is still fun. Be sure to kill weevil larvae by soaking the acorns in 41 ℃ water for 30 minutes, stratify in moist sand in the refrigerator (not freezer), and plant in the springtime.
Pruning
Branches should be pruned to avoid moist pockets or where heavy branches may fall on people or buildings. Avoid having branches that grow with leaves tight together or pressed against buildings. If rain collects in these pockets then molds and fungi can attack. Live oak love having their leaves dry out in a well ventilated breeze.
To ensure that no danger occurs from the brittle hardwood branches, make sure that heavy branches do not hang over walking paths or outbuildings. Also, do not let children play near oaks in a thunderstorm as they are susceptible to falling branches and lightning strikes.
Propagation
Live oaks can be propagated from the acorns produced by the tree. You can also take semi-hardwood cuttings from these plants.
Pests and Diseases
Live oaks are largely pest and disease-free in most areas.
They are prone to leaf blister, powdery mildew and canker, but these don’t do much harm to the tree. You can manage these diseases by removing and destroying any leaf litter.
However, live oaks can also be affected by oak wilt, a serious fungal disease that can be fatal. It has been reported as affecting red, black and live oaks in Texas and a few other isolated areas in South Carolina and can kill trees within a few years. Removing and destroying any infected trees is the recommended course of action.
Care should be taken with cleaning pruning tools to prevent any spread of disease. Live oaks are also not immune to honey fungus.
III. Uses and Benefits
Live oak wood is hard, heavy, and difficult to work with, but very strong. In the days of wooden ships, live oaks were the preferred source of the framework timbers of the ship, using the natural trunk and branch angles for their strength. The frame of USS Constitution was constructed from southern live oak wood harvested from St. Simons Island, Georgia, and the density of the wood grain allowed it to survive cannon fire, thus earning her the nickname “Old Ironsides”. Even today, the U.S. Navy continues to own extensive live oak tracts.
The primary uses for southern live oaks today are providing food and shelter for wildlife. Among the animals for which live oak acorns are an important food source are the bobwhite quail, the threatened Florida scrub jay, the wood duck, yellow-bellied sapsucker, wild turkey, black bear, various species of squirrel, and the white-tailed deer. The tree crown is very dense, making it valuable for shade, and the species provides nest sites for many mammal species. Native Americans extracted a cooking oil from the acorns, used all parts of live oak for medicinal purposes, leaves for making rugs, and bark for dyes. The roots of seedlings sometimes form starchy, edible tubers. People in past centuries harvested and fried these tubers for human consumption much as one might use a potato.
In 1937, the southern live oak was designated the official state tree of Georgia (U.S. state).
Find Where to Buy the Best Southern Live Oak (Quercus virginiana)
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