About Iva frutescens L.
Iva frutescens L. is a species of flowering plant in the Asteraceae family, commonly known as Jesuit's bark, bigleaf marsh-elder, and high-tide bush. This species is native to coastal eastern North America, where it occurs from Nova Scotia along the eastern coast and Gulf Coast down to Texas. It grows as a subshrub or shrub with erect stems that can reach up to 3.5 meters, almost 12 feet, in height. Its leaves are lance-shaped or somewhat oval with toothed edges, and are variable in size, measuring 3 to 12 centimeters (1.2 to 5.0 inches) or more in length. The upper adaxial surface of the leaf is often covered in small warts, a trait that helps distinguish Iva frutescens from other shrubs that grow in the same area. Its inflorescence is an elongated cluster holding many small flower heads with whitish florets. Iva frutescens is very common in salt marsh habitats across its native range. Though it is tolerant of salinity, it does not tolerate flooding well, so it tends to grow in a narrow band along the upper margins of salt marshes. This band may only be a few meters wide, and individual plants growing closest to the water are often stunted. The largest individuals have roots that are submerged less than 7% of the time, and plants grow smaller the longer their roots remain submerged. Its limited tolerance for flooding allows it to compete with other species at marsh margins, and competition from other plants on one side and flooding stress on the other keeps the species restricted to this narrow band. It grows at the front line of waterway erosion, and it sometimes grows on dredged substrate placed along waterway edges. This species provides habitat for salt marsh animals including the marsh wren.
