Silver Lace Fern

How to care for Silver Lace Fern

Light

Pteris ensiformis thrives in bright, indirect light but is one of the more shade-tolerant ferns, making it suitable for positions away from windows. Direct sunlight should be avoided entirely, as it scorches the fronds and fades the silver variegation in ornamental forms. A north- or east-facing windowsill, or a spot set back from a south- or west-facing window, is ideal.

Watering

The compost should be kept evenly moist throughout the growing season, watering when the top centimetre of soil begins to dry. Allow slightly drier conditions in winter but never let the rootball dry out completely, as desiccation causes rapid frond loss. Use room-temperature water, preferably rainwater or filtered water, as this fern is sensitive to fluoride and chlorine found in tap water.

Soil and potting

A loose, humus-rich, free-draining compost is essential. A suitable mix can be made from two parts peat-free multipurpose compost, one part perlite, and one part fine bark or coco coir. Avoid dense, moisture-retaining composts that risk waterlogging and root rot. A slightly acidic to neutral pH of 5.5 to 7.0 is appropriate.

Feeding

Feed with a balanced, water-soluble fertiliser diluted to half the recommended strength every four weeks during spring and summer. Avoid feeding in autumn and winter when growth slows. Over-feeding can cause fertiliser salt build-up, which damages the roots and causes tip browning.

Humidity and temperature

This fern demands high humidity, ideally above 60%. In dry indoor environments, place the pot on a tray of damp pebbles, group it with other plants, or use a room humidifier. Misting can be done but does little to raise ambient humidity significantly. Temperatures should remain between 16 and 24 C. The plant is not frost-hardy and should not be exposed to temperatures below 10 C or to cold draughts from windows and doors.

Repotting

Repot every one to two years in spring when roots begin to emerge from the drainage holes or circle the base of the pot. Choose a container only one size larger, as this fern prefers slightly snug conditions. Terracotta pots help prevent waterlogging. Handle the root ball gently, as the roots are fine and easily damaged.

Pruning

Remove any yellowed, brown, or dead fronds at the base as they appear to maintain a tidy appearance and encourage new growth. No hard pruning is required. Avoid cutting back healthy green fronds, as the plant does not regenerate from bare stems in the same way as some other species.

Is Silver Lace Fern toxic?

Common problems

How to propagate

Division

At repotting time in spring, carefully separate the clump into two or more sections, each with healthy roots and fronds attached. Pot each division into fresh compost and maintain high humidity while the divisions re-establish.

Spores

Collect mature spores from the underside of fertile fronds when the spore cases (sori) turn brown, and sow onto the surface of moist, fine-textured sterile compost in a covered container. Keep at around 20 to 22 C in indirect light; prothalli and then young sporophytes will develop over several months.

Where Silver Lace Fern comes from

Native to India, Sri Lanka, southern China, Japan, Taiwan, South-East Asia including Thailand, Malaysia, and the Philippines, northern Australia, Pacific islands.

Story and origins

The genus name Pteris derives from the ancient Greek word 'pteron', meaning wing or feather, a reference to the feathery, pinnate arrangement of the fronds common across the genus. The species epithet ensiformis comes from the Latin 'ensis', meaning sword, and 'forma', meaning shape or form, describing the elongated, sword-like outline of the fertile fronds. Together the name can be loosely rendered as 'the feathery fern with sword-shaped fronds'.

Pteris ensiformis was formally described by the Dutch botanist Nicolaas Laurens Burman in his 1768 work 'Flora Indica', based on specimens collected from Asia. The species has a long history of cultivation across tropical Asia, where it grows naturally as a component of forest understorey and disturbed rocky habitats. The variegated cultivar 'Victoriae' became popular as a Victorian parlour plant in Britain during the nineteenth century, when fern cultivation, known as pteridomania, reached its height. It remains a favoured subject for terrariums and Wardian case displays, echoing its Victorian heritage.

Varieties to know

Pteris ensiformis 'Victoriae'

The most widely grown cultivar, featuring distinctive silver-white bands along the centre of each pinnule with dark green margins; the variegation is particularly pronounced in bright indirect light.

Pteris ensiformis 'Evergemiensis'

A variegated cultivar similar to 'Victoriae' but with broader, more irregular silver markings across the pinnules.

Pteris ensiformis 'Arguta'

A non-variegated, all-green form with finely cut, elegant fronds, valued for its refined, feathery texture.

Fun facts

• In its natural habitat, Pteris ensiformis can be found growing in limestone crevices and on rocky outcrops, showing a degree of adaptability to alkaline substrates unusual among ferns.
• The species produces two distinct types of fronds: sterile fronds, which are shorter and broader, and taller fertile fronds bearing spore-producing sori along the margins of the pinnules.
• Pteris ferns are among the few plant genera confirmed to hyperaccumulate arsenic from contaminated soils, making some species subjects of scientific research into phytoremediation.
• The silver colouration seen in variegated cultivars is caused by air spaces between the upper and lower leaf cell layers, which scatter light rather than being due to pigmentation.
• Pteris ensiformis has been used in traditional medicine in parts of South-East Asia for treating skin conditions, although such uses are not validated by clinical evidence.

Silver Lace Fern FAQ