This elegant, water-loving fern adds bold structure to sunny or shady areas of the landscape. Also known as water fern, it thrives in acidic, moist or wet soils and can grow up to 5 feet tall and 3 feet wide. Unlike some ferns, it thrives in full sun as long as it has consistent moisture, yet it also tolerates dense shade. It grows in large clumps that spread slowly by rhizomes to form shrubby colonies that stabilize the soil and offer shelter to wildlife. Like other ferns, it’s deer resistant and is an excellent replacement for non-native groundcovers, such as English ivy, periwinkle, and creeping lily-turf. 
 
In spring, a protruding rhizome sends up mostly smooth, pink fiddleheads that lengthen and unfurl into green fronds. One way to identify royal fern is by its fertile and sterile fronds, which differ greatly from each other. The sterile fronds give the fern its vase-like shape and yellow to bronze fall color. They have widely spaced pinnae and pinnules that bear a resemblance to leaves on plants of the Pea family. The erect fertile fronds, which grow in the center of the fern, are topped by green, tassel-like, spore-bearing clusters (another common name is flowering fern) that rise above the fertile fronds from April to June. The clusters mature to brown after the spores are released. 
 
Royal fern is native to the eastern US, with a range extending south to Florida and west to Texas. It’s classified as an obligate wetland plant, which means it almost always occurs in wetlands and is commonly found in swamps, marshy areas, bogs, thickets, low-lying woods, stream banks, and lake shores. However, it’s occasionally seen in drier, more upland sites. 
 
North America has four main species in the Osmunda genus: cinnamon fern, interrupted fern, royal fern (aka American royal fern), and a sterile hybrid fern  located in Virginia. Royal fern, once known as O. regalis var. spectabilis, was recently classified as a separate species, spectabilis, which is Latin for “spectacular.”  One popular theory says that the genus name originates from “Osmunder,” a Saxon name for the Norse God Thor, who hid his family from danger in a clump of these ferns. The common name is either a reference to the plant’s stately appearance or to the "crown" of fertile leaflets that appear at the top of the fertile fronds.
    
Native habitats include bogs, swamps, wet forests, and banks of shores. Use in sunny or shady gardens, woodlands, rain gardens, and along the banks of ponds or streams. 
 
Plant Characteristics:
Grows 2-5’ tall and 2-3’ wide.
 
Prefers part shade; adapts to dense shade or full sun with sufficient moisture.
 
Prefers moist or wet, acidic, rich soils; adapts to rocky soils with some organic matter. Tolerates periods of standing water. 
 
Showy, sterile fronds have 6 or more pairs of widely separated pinnae (leaflets) on pinkish rachis (stems). Each pinna has 8 or more pairs of alternate, oblong-shaped, round-tipped, 2”-long pinnules (subleaflets) with undulating, minutely serrated margins. Fertile fronds are upright with clusters of smaller, branched, sporangia-bearing pinnae. There are no sori, (spore-producing receptacles); the sporangia are naked on the pinnules, which are green before and at maturity and rusty brown after the spores have dispersed from a slit in the top of each sporangium.
 
Semi-erect rhizome forms a mat several inches above the soil's surface. The protruding rhizome looks like a tussock because of the remains of old stipes (bottom part of stalks). 
 
Wildlife Value:
Cinnamon fern hosts 8 species of Lepidoptera in central Ohio, including American angle shade, silphium borer, black arches (all pictured here in order of mention, black arches with its larval form) and marsh fern moths. Osmunda borer moth feeds on the stems and rhizomes. Colonies of royal fern provide cover for small mammals and songbirds.
 
Medicinal, Edible, and Other Uses:
Native Americans used an infusion of the roots for some chronic conditions. The Iroquois used an infusion of the fronds as an anti-convulsive for children.
 
Caution: Osmunda fiddleheads are classified as carcinogenic, especially in large quantities, and should not be eaten.