As sea levels rise and soil salinity increases in Florida, researchers are working to protect the state’s official tree, the cabbage palm (Sabal palmetto). Since 1953, this species has been a key feature of Florida’s coastal areas. Scientists say that these trees now face growing threats from environmental changes.
Amir Khoddamzadeh, an associate professor at Florida International University’s Institute of Environment and Department of Earth and Environment, recently published a study in HortScience examining how young cabbage palms respond to salt stress. The research explores whether adding silicon to the soil could help these seedlings survive in harsher conditions.
Khoddamzadeh became interested in the problem after observing waterlogged palmettos at the Montgomery Botanical Center in Coral Gables. “What will become of Florida’s Sabal palmettos in 20 or 30 years if young palms can’t survive rising salinity?” he asked.
The study was conducted with Patrick Griffith, executive director of Montgomery Botanical Center, and Madhugiri Nageswara-Rao from the USDA ARS Subtropical Horticulture Research Station in Miami. They focused on silicon due to its water-retention properties and its use by NASA for growing plants in space. Silicon is also affordable and widely available.
“We wanted to work on something that ornamental plant nursery producers and landscapers can use,” said Khoddamzadeh.
The application process is straightforward: a few grams mixed with water can help young plants endure stressors like salt exposure.
Researchers grew 96 one-year-old cabbage palm seedlings over twelve months under different salt concentrations. Some received added silicon; their growth, nutrient uptake, development, and survival were tracked. Results showed that silicon improved salt tolerance, increased chlorophyll content—which gave leaves a deeper green color—and led to more leaf production.
A key outcome was establishing the ecological threshold for seedling survival under salty conditions—a finding important for future restoration projects.
“Bringing together the unmatched palms at Montgomery and the fantastic student enthusiasm at FIU is what made it all work,” said Griffith. “I am thrilled to see all the ways that our garden and the university bring these findings to the community. And the fact that this project was student-led is a real bonus — we love seeing the next generation of plant people succeed.”
Khoddamzadeh recommends investing in healthy soils using sustainable materials like silicon rather than relying on fertilizers, which can run off into waterways during rainstorms. Planting mature trees—naturally more tolerant of stress—or increasing native vegetation near coastlines may also reduce damage from saltwater intrusion.
Griffith emphasized simple measures: monitoring palm health closely, responding quickly when signs of stress appear, and choosing planting sites carefully.
Cabbage palms are important not only as symbols but also economically; they support Florida’s nursery and landscaping industries worth over $30 billion annually while providing habitat for native wildlife species.
The research forms part of broader efforts by FIU, Montgomery Botanical Center, and USDA scientists who are testing other crops such as tomatoes, peppers, beans, corn, and cabbage for resistance to salinity—seeking solutions so agriculture across Florida can adapt as sea levels continue to rise.
