Great Fern Diplazium expansum

Great fern is a large perennial plant in the spleenwort family (Aspleniaceae). Its origin is Mexico, Central America, northern South America and islands in the Caribbean. The great fern has an erect growth habit and may grow up to 5 feet tall.  It is found along stream banks, rocky ravines and glades at high elevations. 

This plant thrives in bright, indirect light and shady location. Harsh afternoon sun should be avoided. The soil recommended should be moist, well-drained, high in organic matter, and acidic. Water the plant at the base, avoid getting the foliage wet, and use distilled water or rainwater to prevent mineral build up. This fern should be watered any time the soil feels dry.  A warm humid environment and temperatures between 60 degrees and 77 degrees are needed for optimal growth. Temperatures below 50 or above 86 degrees are not well tolerated. Keep the plant tidy by removing any damaged, diseased, or dead fronds. Pruning is recommended in the spring or early summer. This plant can be propagated by spores, rhizomes, cuttings, or division.

The great fern has fronds that are large, bright green, shiny, erect, lance-shaped, and arching. They can grow up to 5 feet long and 10 inches wide. The spores are located on the underside of the fronds. 

This fern is not hardy outside the tropics and must be grown as an ornamental houseplant or conservatory subject here in North Carolina.

Insects, Diseases, and Other Plant Problems:  Monitor for spider mites and mealybugs. Potential diseases include leaf spot and rust. Soggy wet soils can result in root rot, and direct sunlight can damage the fronds. 

VIDEO Created by NC State Extension's Homegrown series featuring Mark Weathington, Director of JC Raulston Arboretum.