A young, endangered Okeechobee gourd can be seen just below its flower. The 2026 gourd survey resulted in a very successful year for the fruit due to the lower lake levels that allowed the seedlings to take root and spread to areas that previously didn’t have vines growing. (U.S. Army photo)

LAKE OKEECHOBEE — A small native vine is having a big year in the wetlands surrounding Lake Okeechobee.

The federally endangered Okeechobee gourd (Cucurbita okeechobeensis ssp. okeechobeensis) had a strong showing during the 2026 surveys. Relatively low lake levels helped seeds sprout, vines take root, and plants produce flowers and fruit.

Biologists and volunteers spent roughly 160 hours surveying and recorded about 240 Okeechobee gourd plants, 13,012 flowers and 943 fruits. Of those fruits, 141 appeared to remain from the previous year. Teams also found the plants in locations where they had not been documented before, helping build a clearer picture of where the species grows around Lake Okeechobee.

“It was a strong year for both the number of plants and their reproductive activity, which was very encouraging,” said Lee Martin, a U.S. Army Corps of Engineers biologist involved in the monitoring effort. “Overall, this was one of the more encouraging seasons we’ve seen, particularly in the amount of flowering and fruiting we observed.”

A rare vine with deep roots

The Okeechobee gourd occurs in just two widely separated populations—one around Lake Okeechobee and the other along the St. Johns River. Historically, it grew throughout the extensive pond apple forests surrounding Lake Okeechobee, but that habitat looks very different today.

By 1930, at least 95% of the pond apple forests around Lake Okeechobee where the gourd historically grew had been destroyed. Agricultural development and water-level regulation contributed to the loss and alteration of the plant’s habitat. Today, the species still faces threats from habitat loss, altered water conditions and invasive species.

Although the Okeechobee gourd is not used for food, it may help scientists develop crops that can better withstand disease. Early studies found that it could resist or recover from certain diseases affecting squash and other related crops, though the plant can still become infected. For people who have never seen one, the gourd can be easy to miss.

“It’s a small native vine that grows along wetland edges and riparian areas and can be surprisingly easy to overlook if you don’t know what you’re looking for,” Lee Martin said.

The survey team identifies the Okeechobee gourd by its wide, heart-shaped leaves, usually 6 to 8 inches across, with a rough, hairy texture and shallow or deep cuts along the edges. Thin, curling tendrils help the vine climb nearby plants. Its bell-shaped flowers range from yellow to cream, and female flowers have a small gourd growing just beneath them. The fruit develops into a hard, rounded gourd about 3 inches wide and is often light green with pale stripes when young.

The habitat surrounding the vine can be just as distinctive.

“When you are inside an old-growth pond apple forest, it feels like you were transported back in time when dinosaurs roamed the Earth. It’s incredible,” said Jessica Martin, a USACE biologist who helps lead the monitoring program.

Why lower water mattered

Okeechobee gourds are closely linked to the lake’s natural rise-and-fall cycle. They need fluctuating water levels to thrive.

When water stays high for too long, seeds have trouble sprouting, and young plants have less time to take root. As water levels drop, they uncover moist soil where seeds can sprout and seedlings can grow. When the water rises again later, it can carry seeds to new areas.

Survey teams look for gourds along the edges of pond apple forests and wetlands, as well as raised banks of soil, where the vines can climb trees and other plants.

During the 2026 survey season, Lake Okeechobee remained relatively low, which may have given gourds more time and space to grow. Biologists are still studying the conditions to better understand what happened.

“There are probably several factors involved, including water levels, weather and growing conditions, but that’s something we’re still looking at,” Lee Martin said.

The contrast with the previous survey season was striking. In 2025, teams documented 279 plants, 532 flowers and 85 fruits. In 2026, they recorded about 241 plants, but substantially more flowers and fruits: 13,012 and 943, respectively.

At several locations, abundant vines and gourds left a lasting impression on the field team.

“Seeing open areas that were covered in vine and gourds, it reminded you of a pumpkin patch,” Lee Martin said.

The work behind the numbers

Jacksonville District biologists Lee Martin and Jessica Martin lead USACE’s Okeechobee gourd monitoring program, which fulfills monitoring requirements outlined in the Biological Opinion for the Lake Okeechobee System Operating Manual (LOSOM).

This year’s team includes staff from the South Florida Water Management District and the Florida Fish and Wildlife Conservation Commission, Lee County hyacinth control biologists, contractors who control invasive plants and other agency volunteers.

The program builds on previous survey work conducted by the South Florida Water Management District, which collected and provided Okeechobee gourd information to the U.S. Fish and Wildlife Service from 2007 through 2024. Surveys were not conducted, or data were unavailable, in 2017 and 2018.

USACE expanded the survey area, streamlined field methods and increased the information collected. Teams use a standardized survey protocol based on earlier South Florida Water Management District methods and guidance developed with the U.S. Fish and Wildlife Service.

Surveys are generally scheduled from April through July, with timing adjusted to lake levels and field conditions. Lake levels below 13 feet make survey sites easier to reach on foot. Teams prioritize established gourd locations on the south end of Lake Okeechobee, followed by searches of nearby suitable habitat that has not previously been monitored.

Surveyors use Survey123, a digital field-data tool, to record each plant’s GPS location, condition, approximate vine length, and flower and fruit counts, along with surrounding vegetation, lake conditions, weather and other observations. They also estimate fruit age by looking at its appearance: young gourds may be covered in dense hairs and still have a flower attached, while older fruits turn pale and eventually tan, with seeds that may rattle inside. These clues help teams tell whether a fruit grew during the current season or remain from an earlier year.

“We document things like plant locations, vine length, flowers and fruit so we can track population trends and reproductive success over time,” Lee Martin said. “We use consistent survey methods and standardized documentation so the results can be meaningfully compared from year to year.”

Surveyors also take care to minimize disturbance to the plants and the habitat they depend on.

“We collect the information we need while minimizing handling and unnecessary disturbance to both the plants and their surrounding habitat,” Lee Martin said. “We count to the best of our ability without damaging the plants.”

In the wetlands at sunrise

A successful survey does not come easily.

Teams usually start around sunrise to make the most of the cooler morning hours. As the day warms, the thick vegetation and limited airflow make survey conditions hot and humid.

“During a survey, it’s 90-plus degrees and you must walk through grasses taller than me to get to suitable gourd habitat,” Jessica Martin said. “We are usually covered in spiders.”

The job becomes more demanding once a vine is found.

“When you find a gourd vine, you have to determine an estimated length and then start following the vine and counting flowers and fruits,” Jessica Martin said. “These vines go everywhere, from on the ground, under other vegetation to in the trees weaving through the branches. It is a very strenuous survey.”

The work also brings a sense of discovery.

“We get so excited when we find a gourd,” Jessica Martin said. “Of course, there’s some healthy competition to see who can find the first one of the day or the most. To be some of the only people in the world who get to work with this plant species is an honor.”

Continuing the work

A favorable year is encouraging, but it does not answer every question about a species with a limited range and an altered habitat.

“One good year doesn’t tell the whole story, so continued monitoring helps us understand long-term population trends,” Lee Martin said.

The detailed survey results will help guide future monitoring, habitat management and conservation decisions. They also help biologists understand how the Okeechobee gourd responds to changing lake conditions, weather and the availability of suitable habitat.

With sufficient funding, staffing and suitable lake levels, the protocol also calls for surveys of the western and northwestern marshes on a rotating basis every other year. That approach would extend monitoring beyond the established southern locations while keeping the known populations a priority.

For the survey team, the work is an opportunity to contribute to the protection of a plant few people may ever encounter.

“It’s rewarding to see the results of all that time in the field and know that we’re contributing information that can help conserve the species,” Lee Martin said. “Even though many people may never see an Okeechobee gourd, it’s a unique part of the Lake Okeechobee ecosystem, and protecting it helps preserve Florida’s natural heritage.”