With the heat and humidity of Florida, finding plants that are good for that sort of heat and a really moist soil can be a challenge. Wetland plants are great for moist soil conditions. These wetland plants that are good for zones 8 through 11, where Florida falls on the USDA plant hardiness map, are good choices for Florida's moist soil garden plots.
Rhapidophyllum hystrix from the palm family, also known as the needle palm or porcupine palm, is an evergreen wetland plant. It gets 6 feet tall with mostly erect stems that have dark brown to black needles that are 4 to 10 inches long. Leaves are 4 feet long on the stems. Flowers are small and yellow or purple-brown in spring and summer. Grow in moist well-drained soil in full to partial shade. Propagate via seed or division in zones 8 to 10 (not recommended for very southern Florida).
Colocasia esculenta from the arum family, also known as taro or elephant ear, is a fast-growing wetland perennial plant. Leaves are 2 to 3 feet long on a plant 8 feet tall and 8 feet wide. Colors and types of leaves depend on the cultivar. Grow in a moist acidic soil in partial shade. Propagate via seed tubers in zones 8 to 11.
Giant Rose Mallow
Hibiscus grandiflorus from the mallow family, also known as giant rose mallow or swamp hibiscus, is a fragrant wetland perennial that attracts butterflies. It gets 10 feet tall with gray-green leaves that are 10 inches long. Flowers are pink-violet with 6-inch petals. There is a white variety. Grow in full sun in wetland areas. Propagate via seed or division in zones 7 to 10 (not recommended for very southern Florida).
Iris Louisiana hybrids from the iris family, also known as water iris or Louisiana iris, are wetland perennials. Flowers, leaves, colors and sizes are all widely varied depending on cultivar. Grow in shade or sun in moist soil or standing water. Propagate via seed or division in zones 5 to 10 (not recommended for very southern Florida).
Ruellia brittoniana from the acanthus family, also known as the Mexican petunia, is an evergreen perennial that is fast-growing and easy to grow. It gets 3 feet tall with dark green leaves 6 to 12 inches tall. Flowers are trumpet shaped in blue, pink, or white. Blooms get 1 1/2 to 2 inches wide. Grow in moist soil in sun to partial shade. Propagate via cuttings, seed or division in zones 8 to 10 (not recommended for very southern Florida).