Nephrolepis exaltata 'Boston Blue Bell'

History and background of Nephrolepis exaltata 'Boston Blue Bell'

Nurseries were already growing ‘Boston Blue Bell’ by 2000. Growers later used it to develop other named Boston ferns.

It belongs to Nephrolepis exaltata, a species native to tropical and subtropical America. In the wild, these ferns grow in moist forests, swamps and floodplains, on the ground and on trees or palms.

Care routine for Nephrolepis exaltata 'Boston Blue Bell'

• Even light: Place it in bright indirect light and soften strong sun with a light curtain. Turn the pot occasionally so the rounded crown receives light from every side.
• Watering: Check the top layer. Add water once it begins to dry while the potting mix lower down still feels slightly moist. Wet the whole root ball, then let the pot drain.
• Humidity and warmth: Humid air helps the leaflets stay soft. Choose a warm position away from cold windows, draughty doors, radiators and hot air vents.
• Potting mix: Blend fine bark and perlite into peat-free compost. The mix should hold moisture while allowing extra water to escape through the drainage holes.
• Feeding: Feed lightly while the centre is producing new fronds. Use a balanced liquid fertiliser. Choose the lowest dose shown for houseplants and feed again as directed on the label. Use plain water between feeds. Pause feeding when growth slows.
• Grooming: Give the outer fronds room to curve around the pot. Cut fully brown fronds close to the crown and leave healthy pale coils to open.
• Repotting and propagation: Once roots press firmly against the sides, move the plant to a pot one size larger. If water no longer spreads evenly through the old mix and the roots still have space, put fresh mix in the existing pot. Propagate by splitting a well-rooted clump or potting each rooted runner separately.

What to check when Nephrolepis exaltata 'Boston Blue Bell' struggles

• Pale or bleached patches on the window-facing side: Strong sun or heat through glass can scorch the fronds facing the window. Move the plant farther from the glass or add a light curtain. Remove a frond if most of it has dried or browned.
• Fronds quickly turn crisp and drop leaflets: Feel the potting mix before watering. Soak the root ball evenly when it is dry, then let it drain. When the mix still feels damp, move the fern away from heating outlets and improve the humidity around the crown.
• New fronds become long and widely spaced: New growth may weaken when the plant gets too little light or the potting mix dries unevenly or remains wet for too long. If the current spot is dim, place the fern nearer a bright window where direct sun is filtered. When the plant already receives enough light, feel the mix near the edge and centre. Water slowly and evenly if some areas are dry. If the potting mix is still damp several days after watering, wait until the surface starts to dry and check that the drainage holes are open.
• Yellow, limp fronds while the pot stays heavy and wet: Constantly wet potting mix can damage the roots. Slide the root ball out of the pot. Cut off mushy or collapsing roots with a clean tool, stopping where the roots feel firm. Discard the damaged pieces and repot the fern in fresh, loose potting mix.
• Silver marks, webbing, cottony patches or small shell-like bumps: Thrips, mealybugs, spider mites or scale insects may be feeding among the leaflets. Move the fern away from other plants and identify the pest. Use a product labelled for that pest and suitable for indoor ferns. Follow the dose and timing on the label.

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.