Rising seas put Florida’s state tree at risk — new research offers hope
image: As sea levels rise and soils grow saltier, even the iconic Sabal palmetto – the official state tree of Florida also known as the cabbage palm – may be in danger. FIU researchers have discovered that silicon might help young palms survive in salty conditions.
Credit: Photo credit: Daniel Tucker/FIU.
As sea levels rise and soils grow saltier, even the iconic Sabal palmetto – the official state tree of Florida also known as the cabbage palm – may be in danger. But a new study in HortScience suggests a simple, widely available amendment could help young palms survive in salty conditions.
Graduate student researcher, Pedro Gonzalez of Conservation and Sustainable Horticulture Lab and the team of researchers: Amir Khoddamzadeh (Florida International University Earth and Environment Department Institute of Environment), Patrick Griffith (Montgomery Botanical Center in Coral Gables), and Madhugiri Nageswara-Rao (USDA ARS Subtropical Horticulture Research Station in Miami) found that treating young cabbage palm seedlings with small amounts of silicon greatly improves their tolerance to salt stress.
With its sponge-like ability to retain water, silicon —a powerful ally known for its resilience-boosting properties, offers a lifeline for vulnerable young palms by improving physiological processes. Already widely used – even by NASA to grow plants in space – it’s both commercially accessible and affordable, making it a perfect candidate for helping palms survive salinity.
“We wanted to work on something that ornamental plant nursery producers and landscapers can use,” Khoddamzadeh said.
The team grew 96 one-year-old seedlings in a greenhouse for 12 months, watering them with varying salt levels, adding silicon to the soil in different amounts and tracking everything from soil nutrients, plant growth and development to survival rates.
The study also established the ecological threshold for seedling survival – a critical finding for future restoration efforts.
The results show that salinity alone dramatically reduced growth, chlorophyll content, and leaf production, particularly at higher salt concentrations. At 50 ppt salinity (comparable to seawater), untreated seedlings died.
However, when silicon was added, seedlings at moderate salinity (10–30 ppt) maintained higher chlorophyll content, better leaf production and improved overall vigor. Even under more extreme salinity, silicon-treated seedlings partially preserved performance — though survival at the highest salinity remained low.
The implications are serious: cabbage palms are not only a cultural and ecological icon, but they support a multibillion‑dollar landscaping and nursery industry in Florida, generating thousands of jobs.
“Even in all its glory, this quintessential giant is not spared from the growing threats of sea‑level rise and salt exposure,” Khoddamzadeh said.
The researchers say that using silicon is both cost‑effective and simple – just a few grams mixed with water can help young palms survive.
Beyond nurseries, the findings may guide restoration efforts: communities might plant adult palms (more salt‑tolerant) in safer locations or choose native species that better resist salinity.
As South Florida braces for rising seas and increasing saltwater intrusion, this study offers a practical tool to help preserve a symbol of the state.