Heart Fern

How to care for Heart Fern

Light

Hemionitis arifolia thrives in bright, indirect light. A position near a north- or east-facing window is ideal, where the plant receives gentle light without exposure to harsh direct sun, which will scorch the delicate fronds and cause them to curl or brown at the edges. In low-light conditions growth slows considerably and the fronds may lose their deep green colour, so some indirect brightness is important.

Watering

This fern prefers consistently moist soil throughout the growing season, but sitting in waterlogged compost will quickly lead to root rot. Water when the top centimetre of soil feels just barely dry, using room-temperature, ideally soft or filtered water, as the species is sensitive to lime and chlorine. Reduce watering slightly in winter when growth slows, but never allow the rootball to dry out completely as the plant will desiccate rapidly.

Soil and potting

A rich, humus-based mix with good moisture retention but adequate drainage suits Hemionitis arifolia well. A blend of peat-free multipurpose compost with added perlite and fine bark or coir gives the right balance of structure and moisture. The roots are fine and shallow, so the medium should remain loose and aerated rather than compacted.

Feeding

Feed with a balanced, half-strength liquid fertiliser once a month during the spring and summer growing season. Avoid overfeeding as excess nutrients can scorch the roots and fronds of this sensitive fern. No feeding is necessary during autumn and winter when the plant is not actively growing.

Humidity and temperature

High humidity is essential for healthy growth; levels below 50% typically cause leaf tip browning and curling. Misting, grouping plants together, placing the pot on a tray of damp pebbles, or growing in a terrarium are all effective strategies. The ideal temperature range is 18 to 26 degrees C; the plant will suffer below 15 degrees C and should be protected from cold draughts, air conditioning vents, and sudden temperature fluctuations.

Repotting

Hemionitis arifolia is a slow grower with a modest root system and rarely needs frequent repotting. Repot only when roots visibly emerge from drainage holes or the plant has become noticeably pot-bound, typically every two to three years. Choose a pot only one size larger and handle the fragile roots carefully; spring is the best time to carry out this task.

Pruning

Minimal pruning is required. Remove any yellowed, damaged, or dead fronds by cutting them cleanly at the base of the stalk with sterile scissors. Doing so keeps the plant tidy and encourages the development of new growth. Avoid removing healthy fertile fronds unnecessarily, as these carry spores that can be used for propagation.

Is Heart Fern toxic?

Common problems

How to propagate

Spore sowing

Collect ripe spores from the underside of fertile fronds by placing a frond in a paper envelope. Sow spores on the surface of a fine, sterile, moist growing medium such as peat-free seed compost mixed with perlite, then cover the container with a clear lid or cling film and place in a warm, humid spot with indirect light. Germination and development into recognisable plantlets is a slow process, often taking several months.

Division

When repotting a mature clump, carefully separate rooted sections of the rhizome, ensuring each division has at least a few healthy fronds and a portion of intact roots. Pot each section into fresh, moist compost and maintain high humidity to reduce transplant stress while the divisions establish.

Plantlet propagation

Hemionitis arifolia occasionally produces small plantlets at the junction of the stalk and the leaf blade on fertile fronds; once these have developed small roots of their own, they can be carefully detached and potted into moist, fine compost in a humid environment to grow on.

Where Heart Fern comes from

Native to India, Sri Lanka, Myanmar, Thailand, Malaysia, Indonesia, Philippines, southern China, Taiwan.

Story and origins

The genus name Hemionitis derives from the ancient Greek word 'hemionos', meaning mule, a reference to the sterile nature of the fronds in some species of the genus, as mules are famously infertile. The species epithet 'arifolia' is a compound of 'Arum' (a genus whose leaves the heart-shaped fronds resemble) and the Latin 'folia', meaning leaves, thus translating as 'arum-leaved'. Together the name reflects both the genus's historical botanical character and the distinctive leaf shape that sets this species apart.

Hemionitis arifolia was described scientifically by Thomas Moore, the British pteridologist, in the mid-nineteenth century, drawing on earlier work by botanists documenting the fern flora of South and Southeast Asia. The genus Hemionitis itself has a long history in botanical literature, having been recognised since the work of early European naturalists exploring tropical regions. The heart fern has never carried strong formal cultural symbolism in Western traditions, but its striking foliage has made it a collector's plant among fern enthusiasts since the Victorian fern craze, known as pteridomania, brought exotic ferns into fashionable cultivation across Britain and Europe.

Varieties to know

Hemionitis arifolia (standard species)

No widely recognised cultivars have been formally named; plants in cultivation are essentially the straight species, though leaf size and shape can vary somewhat between individual specimens

Fun facts

• Hemionitis arifolia is one of very few ferns that produce clearly heart-shaped fronds, making it immediately recognisable among its relatives.
• The species displays dimorphic fronds, meaning fertile fronds and sterile fronds are structurally different on the same plant, a feature seen in only some fern genera.
• In its native habitat the plant often grows as a lithophyte, anchoring itself to mossy rocks and cliff faces rather than growing in conventional soil.
• Despite being a fern, its dark, wiry, almost black petioles give it an appearance quite distinct from the feathery fronds most people associate with the group.
• The sporangia on the underside of fertile fronds are arranged along the veins in a characteristic pattern called catadromous venation, which is a taxonomic feature of the genus Hemionitis.

Heart Fern FAQ