Tillandsia recurvata, or ball moss
Drive through Baton Rouge’s Beauregard Town or Spanish Town neighborhoods hand you can hardly help but notice the change: the crepe myrtles that have provided a graceful canopy to these streets for generations are fighting for their lives. Choking beneath constricting layers of ball moss, the city’s crepe myrtles are slowly but surely having the life squeezed out of them. Like Spanish moss, ball moss (Tillandsia recurvata) is a member of the Bromeliad family of epiphytic plants that derive nutrients from the air, rather than from the host tree itself. The difference with ball moss, though, is that rather than simply hanging over a tree’s branches, it attaches tightly to the bark of trunk and limbs, then proceeds to spread aggressively. Left unchecked, ball moss clusters can become thick enough to deprive the host tree of air and light, constrict limb growth, break branches, and eventually kill it entirely. The infestation, which affects live oaks, magnolias, gardenias and cedars as well as crepe myrtles, has become severe enough that local organizations including Baton Rouge Green and the LSU AgCenter have established resources and educational programs. But in Beauregard Town—arguably ground zero for Baton Rouge’s ball moss infestation—local resident and self-professed tree nut Scott Purdin is taking the fight to the canopy, one tree at a time.
“Initially, [ball moss] is slow to spread, but once it gets established, it moves fast!”—Scott Purdin
“I love trees; there are forty to fifty varieties I’ve planted myself,” said Purdin, a lifelong Baton Rougean who has lived on a leafy Beauregard Town block for decades. As ball moss spread through his neighborhood, Purdin followed the two courses of action for ball moss control recommended by the LSU AgCenter and others:
- Hand-pull moss from a tree’s limbs and branches (and seal it into trash bags for disposal), which re-exposes leaves and branches to light and air.
- Spray the moss with a solution of two parts water to one part baking soda, dissolved in a garden sprayer, which will kill the moss’s flowers, thereby inhibiting the spread of pollen.
But Purdin noticed that even after a tree’s lower branches (i.e. the ones easiest to reach) were freed of moss, the infestation would quickly recur. “Initially, [ball moss] is slow to spread, but once it gets established, it moves fast!” he said. “Ball moss seems to form a kind of soil on the branch surfaces. Then, when the pollen drops, new ones grow out of that. You can clean it off (which is a lot of work), but all it takes is a little ball moss somewhere on the tree, and it comes right back.” He surmised that the remaining colonies high in the tree tops were dropping pollen on the cleaned, lower branches and re-infesting them.
That’s where the baking soda comes in. “Baking soda is an alkaline in an acidic universe,” Purdin explained. “It kills the flower. So, if you spray a tree with baking soda and kill the flowers, you’re not getting pollen dropping anywhere.” He advises that this can be achieved with a simple, two-gallon garden sprayer, although one with an inbuilt agitator to prevent the baking soda from settling and clogging the sprayer works best.
Of course, getting gallons of baking soda solution to the crown of a forty-foot-tall crepe myrtle isn’t easy, and to better facilitate his eradication campaign, Purdin has launched Ball Moss Control, a foundation dedicated to restoring the health of Baton Rouge’s urban canopy by providing accessible education, tools, and support services to treat and control ball moss infestations. His foundation is collaborating with Bofinger’s Tree Service to procure a commercial sprayer truck capable of directing baking soda solution high into the canopies of Beauregard Town’s tallest crepe myrtles. “We’ve got to start spraying our trees,” he said. “With this truck, we’ll spray for ball moss five days a week. I’ll start in our neighborhood, then I’ll move downtown, and I’ll do it again and again, until there’s no more pollen dropping.”
