Nephrolepis exaltata 'Boston Blue Bell'

Species origin and Boston fern history

Nephrolepis exaltata is native to tropical and subtropical parts of the Americas. It inhabits moist forest, hammocks, swamp and floodplain settings, growing either on the ground or as an epiphyte on trees and palms.

The familiar Boston fern arose as a drooping horticultural selection from the more upright wild sword fern. “Boston fern” now covers a broad horticultural group rather than one identical clone.

‘Boston Blue Bell’ is a compact, cool-toned cultivar within this horticultural group. It was selected in cultivation rather than found as a wild regional form.

Care for healthy fronds

Moisture: Nephrolepis ‘Boston Blue Bell’ should not dry out completely. Water as the surface begins to dry, wetting the full root ball before letting the pot drain.

Light and climate: Bright filtered light maintains the compact, cooler-toned fronds. Dim conditions loosen the plant, while hot direct sun can bleach foliage raised under cover.

Soil and nutrition: Use a loose fern mix that combines moisture retention with open air spaces. Feed at a low dose while fronds are developing.

Grooming and propagation: Cut fully brown fronds at the base without damaging new fronds as they unfurl. Division and young plants rooted along creeping runners preserve the cultivar; spores do not reliably reproduce a named cultivar.

Health checks for Nephrolepis exaltata 'Boston Blue Bell'

• Regular brown dots: Repeated sori beneath mature leaflets are reproductive structures. They remain fixed in an orderly pattern; scattered cotton, shields or webbing are not sori and should be examined for pests.
• Rapid crisping: Fine leaflets can brown and fall soon after the root ball dries completely. Wet the full pot, allow drainage and restore a steadier moisture rhythm; fully crisp tissue cannot recover.
• Yellowing in a heavy pot: Limp yellow fronds above old saturated substrate indicate low oxygen around roots or crown. Pause watering until the condition is checked, clear blocked drainage and renew decomposed mix when necessary.
• Long, loose new fronds: A compact plant becoming increasingly open usually needs more bright filtered light. Improve brightness without moving it directly into hot sun and judge the correction from the next fronds.
• Bleached outer foliage: Dry pale sections on the most exposed side follow excessive direct sun. Reduce that exposure and maintain filtered light; scorch is permanent on the affected leaflets.
• Mites, thrips and waxy pests: Mites stipple and bronze the underside, thrips silver and distort young fronds, mealybugs form cotton, and scale forms attached shields. Keep the fern apart, inspect the crown and treat the confirmed pest.

Nephrolepis exaltata ‘Boston Blue Bell’ is non-toxic to cats and dogs

• This plant is non-toxic to cats and dogs.
• Its effects on people are unclear, so keep it away from young children who may chew it.
• Eating a large amount can still cause an upset stomach. Seek medical or veterinary advice if symptoms continue.

The meaning and history of Nephrolepis exaltata

Greek nephros, kidney, and lepis, scale, form Nephrolepis and refer to the small kidney-shaped coverings over the spore-bearing patches. Exaltata means elevated or very tall.

Heinrich Wilhelm Schott established the genus Nephrolepis in 1834 in Genera Filicum (Vienna), plate 3.

Carl Linnaeus first described it as Polypodium exaltatum in 1759 in Systema Naturae, tenth edition, volume 2, page 1326. Heinrich Wilhelm Schott later placed it in Nephrolepis as Nephrolepis exaltata in 1834 in Genera Filicum (Vienna), plate 3.