Sam Irwin
So you just bought a new house and you’re going to become the Lawn Master? Well, take it from me, a grizzled veteran of lawn nurturing—it ain’t that easy.
If you’re lucky enough to live in one of those new neighborhoods with three feet of lawn between houses and no hundred-year-old oaks, read no further. Throw some St. Augustine sod down and let the sun do its work.
I live in Mid City Baton Rouge. Mid City is so full of “stately oaks and broad magnolias,” it’s practically a cliché. I have been trying to grow grass under my oak trees for twenty-five years with limited success. Can you say “leaf management”? The best things you can do with oak leaves in order of priority are 1) compost them, 2) mulch them, 3) mulch and use them on a pathway or 4) rake ‘em, bag ‘em and chuck ‘em. DO NOT rake them up and pile them against the trunk and over the roots. That invites disease to attack the tree.
Mayhew, like me, holds out a glimmer of hope that one day he’ll have a lush lawn that can grow under a shady oak.
Years ago, I served as press secretary for the Louisiana Department of Agriculture and Forestry. Being LDAF press secretary does not guarantee horticultural nirvana, but I did learn a lot about agriculture. Mostly what I learned is if you want to grow something successfully, ask an expert. I have quite a Rolodex of horticulturists I can call upon who respect my quest.
I asked Zeb Mayhew, executive director of Oak Alley Plantation if they had a lawn plan. Thousands of visitors trek to Oak Alley, and across their lawn, to admire the architecture and horticulture of our southern climate.
[Read this: Native plants are for the birds.]
“We’re trying to figure it out because it’s hard to grow grass under the trees,” said Mayhew. A vast understatement.
It’s not for lack of expertise or funding either.
“We have a staff of eight for the gardens,” he said. “The [lawn] budget ends up being whatever it is. If the chinch bugs go after you, you double down. We aerate, we fertilize, we weed control.”
In the alley itself, Mayhew said they have reluctantly resorted to placing mulch under the canopy to the tree drip line. The mulch provides habitat for beneficial nematodes and limits muddy shoes. Obviously, you don’t want thousands of guests tracking mud through your house of history.
Trying to grow grass under oak tree shade is like “watching puppies die.”
But Mayhew, like me, holds out a glimmer of hope that one day he’ll have a lush lawn that can grow under a shady oak.
“The bottom line is we’re on a quest for something that will be hardy, long lasting, healthy, and resistant. There is experimenting going on, mostly in zoysia grass,” Mayhew said.
At the forefront of this experimentation is LSU AgCenter scientist Ronald Strahan. Doc Strahan, working with LSU AgCenter county agent Craig Roussel, is conducting a two-year study at Oak Alley of St. Augustine and zoysia, two grasses alleged to do well in the shade. Their conclusion? Trying to grow grass under oak tree shade is like “watching puppies die.” I won’t tell you which researcher said it that way, but it’s true. It’s terrible to watch your freshly-planted baby grass wither and die. I have experienced that pain.
“It’s not just the shade,” said Strahan. “It’s the compaction of soil. It’s the lack of sunlight. It’s the lack of air movement. We were there every sixty days to observe the grass. The soil [under oak trees] is very compacted. When we sodded, we couldn’t till the soil properly because of the root system. It’s under stress immediately.”
It’s just a matter of time, two years, they said, before the grass withers and dies.
If you are determined to grow something green under your noble oak, consider these choices: Boston fern (dies back in a freeze), Asiatic jasmine (hard to keep under control), iron plant (boring), liriope (typical) and mondo/monkey grass (mowable). In my yard, my wife planted a few trailing ruellia and it volunteers easily. It’s ground cover, it’s different, makes a pretty violet flower, and there’s less area to mow.
But you know what does really well under oaks? Lawn chairs and sweet tea. You could even hang a nice swing from yon oak branch and enjoy the shade.
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