The tree gets its name because the species is an evergreen oak which is often confusing. After all, a few evergreen oaks are called “live oaks.” Because of this, it is most often called southern live oak or, better yet, its botanical name. If you consider growing this beautiful giant, realize that its hardiness zone is tiny, you will need plenty of space for your tree to grow into, both height and width-wise, and the pruning required to help it get established can be a chore. The biggest concern you will face when taking on the care of a young southern live oak is setting up a pruning routine. This guarantees that your tree will have the proper structure to allow clearance underneath its branches and strength to withstand the next four to nine centuries.
Light
Unlike most oaks, the southern live oak can actually tolerate some shade. It will perform best in full sun, but it can manage in partial shade without suffering. Often the only objects that can cast a shadow on this are buildings or other live oaks, so this is a good example where some advanced planning can play a part in giving your tree the best conditions possible.
Soil
The southern live oak is highly adaptable and will do well in soils with high alkalinity and wetness. It does have its preferences, well-draining acidic soil, but the tree is so adaptable that no negative issues will be seen if these preferences aren’t met.
Water
Upon planting, regular weekly watering will need to be done to help your oak establish itself. After the first couple of seasons, supplemental watering will not be much of a concern. The normal amount of 10 gallons per inch of trunk measured by caliper at knee height is a good gauge. Following the first two years, you can taper off your watering routine. Live oaks are extremely drought resistant when established, so there is no need to worry about your tree not getting enough water.
Temperature and Humidity
The live oak is the tree of the deep south; it thrives on heat and humidity and will outright die in places that do not offer up the balmy climate of its native range. It is highly adaptable in many conditions; temperature is not one of them. If your location is not in USDA Zone 8-10, another tree might be best for your landscape.
Fertilizer
Your oak will not need any supplemental fertilizer. If you believe that the tree is suffering some setbacks due to nutrient deficiencies, first test the soil and be sure if you do find that some nutrient deficiencies, you will know the exact NPK formulation to set things in balance—correct things by using a slow-release fertilizer formulated with the nutrients you need. Usually, a general-purpose fertilizer will do fine.
Pruning Southern Live Oak
Without a doubt, the single most important thing you will need to do is to prune your live oak beginning the first year after your oak was planted while it is dormant (July to December). Your main goal is to establish a single dominant leader branch and remove any later growing branches growing about 2/3 up the tree. You are essentially lifting the canopy. This ensures that the large lateral branches do not intersect and create a cluster or nest that blocks passage under the tree. Mark this task on your calendar for the first five years of the tree’s life, and plan to do it every five years until age 30. Eventually, the weight of the lateral branches could bring them into contact with the ground, but you can help keep this at bay with a regular pruning schedule.
