Grasses, rush and sedge grow in wet prairies. Fire and flooding squeeze out the plants and trees that don't belong in these areas. Drainage for agriculture is the main reason for marsh losses. The marshes that remain are mostly unsuitable for agriculture or are protected under wetland regulations. These wetlands usually occur where slow-moving or still water is present most of the year.
Cypress trees grow out of standing water.
The soils are flooded from four to eight months a year. The soil drains slowly. Fire helps keep other trees from establishing themselves here. After a fire, the cypress trees quickly grow back. Cypress swamps are protected under conservation laws.