With its short-stalked, elegantly drooping fronds, this plant is the archetypal fern. About 30 species are distributed throughout the tropics and subtropics all over the world where they flourish so abundantly that they are considered as weeds in gardens. Their great proliferation of shoots means that they can spread rapidly and will soon cover the entire surface of a pot. The fronds of some species may grow a metre (40 in) long. The pure species possess simple-feathered fronds. The individual leaflets are more or less curled or wavy, the edges serrated or lobed. Thedevelop in kidney-shaped clusters at the ends of the lateral veins. The fronds are ideally suited for use as greenery in flower arrangements or bouquets.
• Nephrolepis exaltata is the species most often offered for sale, and with the most varieties. The oldest variety, which is still available today, was discovered in America in 1870 and became famous under the name “Bostoniensis” or simply as “Boston fern”. Many other varieties have derived from this early ancestor. There are now many different types, with varying shades of green, simple or multi-feathered fronds and different rates of growth. Some more compact varieties are “Boston Dwarf”, with upright growth, “Maassii” with relatively smooth fronds, or “Teddy Junior” with wavy fronds. “Rooseveltii”, on the other hand, grows large and spreading. “Little Linda” and “Veronica Lace” are small, fine, multi-feathered, densely growing types.
• Nephrolepis cordifolia possesses stiffer, dark green fronds that grow up to 60 cm (24 in) long but are only about 5 cm (2 in) wide.
A special feature of this species is the underground tubers that appear at the ends of the shoots. The varieties most often for sale are usually “Compacta”, which remains small, or “Plumosa”, the feathery leaves of which are divided in their outer halves. The unusual variety “Duffii” has very narrow fronds with almost round, very light-coloured leaflets for this species.
• Nephrolepis biserrata is a very vigorously growing species with fronds that may grow up to a metre (40 in) long when cultivated. The frond ends of the variety “Furcans” (sometimes also grouped under Nephrolepis falcata) are forked several times.
Origin: Nephrolepis exaltata and Nephrolepis biserrata are distributed throughout the tropical regions of the world. Nephrolepis cordifolia occurs in tropical Asia and New Zealand. Nephrolepis may grow terrestrially but also as an epiphyte.
Position: Bright to semi-shady. No direct sunlight but it will cope with more light than many other ferns. Stable room temperature all year round; in winter not below 18° C (64° F). This plant loves high humidity.
Care: Constant, even humidity is particularly important for this fern. Do not allow it to dry out but avoid water-logging! The best way to fulfil these requirements is by using clay peg irrigation. Nephrolepis cordifolia can cope with a little more dryness. Give a weak dose of fertilizer fortnightly from the first month of spring to the first month of autumn. Mist over frequently.
Varieties that grow vigorously should be repotted every year; others only when necessary in the spring.
Propagation: From rhizomes or division; the species also from. In the case of Nephrolepis cordifolia, you may also propagate from tubers with a section of the rhizome. Nephrolepis exaltata is usually propagated by in specialist nurseries as many varieties do not produce spores.
Pests, diseases: Spider mites are encouraged by too low humidity, Also Diptera, Sciaridae. Pale green feathers that are finally shed indicate a rootstock that is too wet or too dry or a position that is too dark.