Tough and easy to grow, these are the most widely used of all ferns. Where winters are cold, they're popular houseplants, benefiting from well-drained soil, frequent misting, and monthly applications of a general-purpose liquid houseplant fertilizer from spring through fall. In frost-free areas, they make splendid ground covers for shady areas. Not usually browsed by deer.
N. biserrata. GIANT SWORD FERN. Native to the tropical Marquesas islands, this species is known primarily for the selection 'Macho'. Arching fronds grow 3 4 ft. long and 67 in. wide, making a plant 56 ft. wide. Bright shade or morning sun is ideal. Often grown as a summer annual. Container plants fill their pots quickly; daily watering is necessary.
N. cordifolia. SOUTHERN SWORD FERN. Native to many tropical regions of the world. To 23 ft. tall, 5 ft. wide. Tufts of bright green, narrow (2-in.-wide), upright fronds with closely spaced, finely toothed leaflets. Roots often have small, roundish tubers. Plant spreads by thin, fuzzy runners and can be inva- sive. Will not take hard frosts but is otherwise adaptable, tolerating poor soil and erratic watering. Good in narrow, shaded beds; can thrive in full sun with adequate water. Good in pots and hanging baskets. Often sold as N. exaltata. 'Lemon Buttons' grows to 1 ft. tall and wide with short, rounded leaflets, making the frond only an inch wide. It's named for its scent, not its color.
N. exaltata. SWORD FERN. Like N. cordifolia, this is a tropical species, but it grows larger (to 7 ft. high and as wide) and has broader fronds (to 6in. wide). Most common are named selections grown as houseplants. Best known is 'Bostoniensis', Boston fern. Growing about 3 ft. high, it is the classic parlor fern, with spreading, arching habit and graceful, eventually drooping fronds broader than those of the species. Among the many forms with more finely cut and feathery fronds are 'Fluffy Ruffles', 'Rooseveltii', and 'Whitmanii'. 'Rita's Gold' has 18- to 24-in. fronds of bright lime-green, demanding shade but giving the illusion of light wherever it is grows.
N. obliterata. From northwestern Australia. Grows to 3412 ft. high and wide. Similar to N. cordifolia but has darker green, somewhat narrower fronds. Used mainly as a houseplant. Habit is stiffer and more erect than that of N. exaltata 'Bostoniensis', and plant is more tolerant of low humidity and both high and low light conditions. Selections include 'Kimberly Queen' and 'Western Queen'. 'Medusa' grows about half the size of the species, with compact fronds that tend to curve, creating the illusion of tangled hair.