For this brief owner’s guide to live oak care, I consulted with professional arborist, horticulturist, and instructor, Jim Foret, who has extensive experience with old live oaks in the New Iberia area and teaches at the University of Louisiana at Lafayette. I asked him to address the importance of this distinctive tree species for Louisiana and to focus his comments on its care and conservation. I’ve distilled his guidance into three guiding principles for live oak owners and caretakers.
Roots and soil—It takes room to grow a fine tree, so don’t crowd your oak. Few people grasp just how large the functioning root system of a live oak really is—your oak’s roots do not stop at the end of its branches but generally extend one-and-a-half to two times the full spread of its crown.
Caring for your oak tree begins with creating the best conditions for a healthy root zone and lower trunk. Every square foot of undisturbed, uncompacted soil in an oak’s root zone is GOLDEN to the health of the tree. Caring for the “lower trunk” means keeping the above-ground root flare clear of leaves and soil that can eventually accumulate and weaken the root system.
Oaks don’t like soggy or compacted soil. They may tolerate it for a short time, but these two conditions block oxygen in the soil that an oak needs to thrive, and compacted soil makes it harder for oak roots to grow. Eventually, these conditions can literally smother a tree.
Balance—Live oaks are amazingly strong, within limits. The Creator designed them to grow in forests but people have stripped the forests and left them often standing alone or in groves where they can grow much wider, with multiple major limbs. These long spreading branches can become massive and sometimes could be poorly attached to the main trunk structure.
A balanced shape can improve an oak’s life span. Prune oak limbs (ideally when they’re young) to avoid imbalance, lopsidedness, and excessive limb length and weight that might literally pull the tree apart as it grows. Prune during the dormant winter months when the oak is less active, and don’t remove more than 10 to 15 percent of branch growth a year to prevent over-stressing the tree.
Leave the leaves—Your oak’s leaves, as with other plants, convert light (radiant energy) to chemical energy. Every leaf is important and necessary to your oak’s vitality. Leaves on the outside of the canopy are designed to absorb bright direct sunlight, while leaves growing inside the oak’s canopy are designed to extract the most energy from filtered light. Both types of leaves are crucial for your oak’s health. So prune carefully and cautiously and leave the healthy limbs and leaves on your tree.
If you’re fortunate enough to live in the company of live oaks, your life is blessed. And if you don’t live near a live oak, I strongly urge you to plant one, or maybe two or three.