Nephrolepis exaltata aka Boston Fern

Nephrolepis exaltata is known as Boston fern or sword fern. It comes from tropical and subtropical parts of the Americas. This perennial fern grows in soil or on other plants. It keeps its green fronds year-round in suitable conditions. Garden plants often reach 2–3 feet (0.6–0.9 metres) tall and wide. RHS gives an upper height of 3.3 feet (1 metre). Its spread can reach 4.9 feet (1.5 metres). Wild plants may reach 7 feet (2.1 metres) tall.

The plant forms clumps of slim, pale green fronds. Young fronds rise upright, then bend outward as they age. Each pinnate frond has many small leaflets along its length. The leaflets have uneven bases and fine teeth along their edges. Short rhizomes send out thin runners that can form new plants. This fern has no woody trunk or bark. It makes neither flowers nor fruit. Instead, round clusters beneath the fronds hold its spores. These dark marks are normal, not signs of pests.

Indoors, give it bright, filtered light without direct sun. Outdoors, it grows in partial or deep shade. Use moist soil that drains well and contains organic matter. High humidity helps keep the fronds in good shape. Keep the soil from drying out, but reduce watering in winter. Established outdoor plants can withstand brief dry spells. Sources differ on its outdoor hardiness. Missouri Botanical Garden and Chicago list USDA zones 10–12. Florida's guidance gives zones 8b–11. RHS rates it H1B, allowing summer use outdoors in Britain.

Its arching fronds suit hanging baskets, pots, and raised planters. Indoors, a stand gives the fronds room to hang. In warm gardens, groups can cover shaded ground beneath trees. It also works as an accent beside pools or paving. Deer tend to leave it alone. Runners can spread fast in warm, favorable sites. Edging and thinning help keep plants within their space. Divide clumps or separate rooted runners to make new plants.

Dry air can invite scale insects and spider mites. Mealybugs, whiteflies, slugs, snails, and fern caterpillars may also cause trouble. Dry soil can lead to frond loss. Low winter humidity can turn the tips brown. Excess water can cause root or frond rot. Remove dead fronds to keep the clump tidy. ASPCA lists it as non-toxic to cats, dogs, and horses. The supplied sources do not establish any edible parts.