LSU AgCenter Horticulturist
(02/28/20) Live oaks have a strong history in the Gulf South. Before steel, bronze and aluminum alloys were used, U.S. naval ships were built from the strong wood of live oaks. They produce wood that is close-grained, hard and durable and is one of the heaviest woods that grows natively in America.
This durable wood made it a suitable material for building warships for the U.S. Navy. According to the Gulf Islands National Park Service, the U.S.S. Constitution’s inner hull (1795) was built from live oak lumber. And because of its proven resilience in the War of 1812, it earned the name “Old Ironsides.”
The first national tree farm was established in Pensacola, Florida, by President John Quincy Adams and Samuel S. Southland, secretary of the navy, for building and maintaining navy warships. The areas were called live oak tree reservations, and they now remain as national parks. One that is close to home is the Naval Live Oaks Reservation in Pensacola, Florida.
Metal began to replace wood after the American Civil War. Today, oaks still hold an iconic status for resilience in the Gulf South. After devastating hurricanes and floods, it is often our live oaks that remain standing.
A slight controversy surrounds the live oak, however. Is it deciduous? Is it evergreen? Is it semi-evergreen or semi-deciduous? Consult any number of reference books, and you will find it called all of the above.
Live oak (Quercus virginiana) is a very large, slow-growing, long-lived tree. The largest live oak specimen in Louisiana is located in Mandeville and has been named the Seven Sisters oak. It has a whopping spread of 132 feet and a trunk 37 feet in diameter. One of the oldest live oaks in the South, the Angel oak, is located in Charleston. It is said to be about 400 to 600 years old.
Many of the plantations in the South and especially in Louisiana, date back to before the American Civil War and have alleyways lined with oak trees that still live today.
William Guion, a natural landscape photographer, documented and wrote a book Quercus Louisiana: The Splendid Live Oaks of Louisiana. In the book, he references Edwin Lewis Stephens, the first president of the University of Louisiana at Lafayette.
Stephens created the Live Oak Society and was responsible for planting oak seedlings at the intersection of University Avenue and Johnston Street that are now known as the Century Oaks. He believed the live oak should have been named Quercus louisiana, not virginiana because of vast number of live oaks found in this state.
So, back to our controversy. Are live oaks evergreen or not? They do keep their leaves year-round, except for a short couple of weeks in late winter or early spring when they shed all of their leaves from last year’s growth and then re-grow their entire canopy.
Simultaneously, as the leaves fall, live oaks produce male flowers called catkins, which produce copious amounts of pollen. The pollen turns the tops of cars, houses and any surface it can stick to a yellow-green powdery mess and creates headaches for allergy sufferers.
The flowers then die back, turn brown and fall to the ground, releasing yet another assault on the ground and surrounding area.
So, yes and no, live oaks are evergreen. They do keep their leaves year-round except for a small window. The leaves that are dropped make a great mulch. Rake them up and put in your compost or recycle them and use them for mulch.
The best time to plant live oaks in fall or winter. The trees have a massive surface root system, so be sure to plant live oaks far away from houses, sidewalks and driveways. The root systems can break foundations as well as concrete sidewalks and driveways. Additionally, live oaks can grow to a substantial height, so also consider overhead power lines.
Another gorgeous characteristic of live oaks is their natural low, sweeping braches that sometime touch the ground. Keep this in mind when planting. They will need lots of room. Try to plant away from streets to prevent having to trim low-growing branches, forcing the trees to grow in an upright, unnatural way.
When they are full grown, live oaks will create a great deal of shade. This will cause an issue for plants and turfgrass growing underneath trees that cannot tolerate shade. St. Augustine and centipede turfgrass are the most shade tolerant.
The shade provided by oak trees can help save cooling energy costs in the summer. Not much maintenance is required. Small trees will take years, maybe your lifetime, to grow to their full potential. It is a wonderful thought to consider leaving a legacy of such a fine oak to be enjoyed in your family generation after generation.
Live oaks are so unique and such an important part of our history. These trees hold human stories connected to the families they have outlived. And some have been here since before the arrival of the first Europeans. Don’t you want to continue that legacy?
The Edna Szymoniak Oak graces the entrance to the LSU AgCenter Hammond Research Station. Photo by William Guion
Small live oak trees will one day grow to be massive specimens requiring substantial space. Photo by Heather Kirk-Ballard/LSU AgCenter
When shedding leaves, live oaks simultaneously produce catkins, or male flowers, that create copious amounts of pollen. Photo by Heather Kirk-Ballard/LSU AgCenter
Live oaks shed their leaves every year in late winter. Photo by Heather Kirk-Ballard/LSU AgCenter