licorice fern Care (Polypodium glycyrrhiza)

This fern prefers low to moderate light similar to a shaded forest floor.

• Provide bright, filtered light or open shade, such as dappled light under trees for 2–4 hours, avoiding direct midday sun.
• Tolerates deep shade but fronds may grow thinner and more sparse if light stays below about 2 hours of soft, indirect light daily.
• In hot summers, allow only early morning or late afternoon sun; excessive direct sun scorches fronds and dries rhizomes of licorice fern.

Moist but not waterlogged conditions suit this fern best.

• Water when the top 2–3 cm of soil or substrate feels just barely dry, aiming for consistently damp but not soggy conditions.
• Ensure very sharp drainage around rhizomes; standing water causes root and rhizome rot, seen as black, mushy tissue and a sour smell.
• Reduce watering in late fall and winter when growth slows, but do not let soil fully dry; crisping frond tips usually indicate underwatering in Polypodium glycyrrhiza.

This fern is adapted to cool, mild climates with moderate seasonal shifts.

• Active growth occurs around 50–70°F (10–21°C); it handles typical coastal and woodland temperature swings well in these ranges.
• Tolerates brief drops to about 20°F (-7°C) once established, but repeated hard freezes can damage fronds, which may die back and re-sprout from protected rhizomes.
• Handles short warm spells up to about 80–85°F (27–29°C) if shaded and kept moist; prolonged heat plus dry conditions stresses the plant and can desiccate rhizomes.

This fern needs consistently moist air to thrive, especially indoors or in heated homes.

• Aim for 60–80% humidity using a humidifier, pebble tray, or placement near other plants to create a moist microclimate.
• In dry air, fronds brown at the tips, curl, and feel crisp rather than flexible.
• Keep soil slightly moist while raising air humidity; avoid misting so heavily that fronds stay wet for hours, which encourages leaf spot.

Polypodium glycyrrhiza prefers loose, organic-rich, well-aerated substrates that mimic decomposing wood or mossy rock.

• Use a mix of 50–70% fine orchid bark with peat or coco coir and a small amount of compost to supply organic matter.
• Ensure rapid drainage by adding perlite or pumice so water flows through in seconds rather than pooling on the surface.
• Aim for slightly acidic conditions, around pH 5.5–6.5, which support nutrient uptake and healthy rhizome growth.
• Avoid dense garden soil, heavy clay, or mixes that stay soggy, as these reduce oxygen around the rhizomes and promote rot.

This species can adapt to container culture when the pot and medium are chosen for rhizome spread and fast drainage.

• Select a wide, shallow container so rhizomes can creep horizontally rather than forcing them into deep, compacted layers.
• Choose a lightweight pot material if the plant is moved often, but use a heavier container outdoors to keep spreading fronds stable in wind.
• Raise the pot slightly on feet or spacers so drainage holes stay clear and runoff leaves the container quickly after watering.

This fern is adapted to low-nutrient forest habitats, so licorice fern needs only light, infrequent feeding in cultivation.

• Use a mild, balanced liquid fertilizer (around 10-10-10) at 1/4–1/2 strength during active growth in spring and early summer.
• Apply every 4–6 weeks at most, only when the plant shows steady new frond growth.
• Skip synthetic fertilizers on wild or established outdoor clumps; use a thin layer of leaf mold or compost instead.
• Stop all feeding in late fall and winter when growth slows or fronds die back.

Pruning needs for Polypodium glycyrrhiza are minimal and focus on hygiene rather than shaping.

• Best time is late winter to early spring, just before or as new fronds emerge.
• Remove dead, yellowed, or damaged fronds at the base with clean scissors or hand pruners.
• Thin out crowded or overlapping fronds only where airflow is poor, keeping the natural arching habit.
• Disinfect tools before and after use to reduce the risk of fungal and bacterial problems.

This species is usually grown on logs, rocks, or as a groundcover, so attention centers on careful transplanting rather than frequent repotting.

• Plan moves in early spring or early fall when temperatures are mild and moisture is reliable.
• Look for signs such as rhizomes creeping far beyond the intended area or containers filled with circling roots.
• Transplant with generous portions of attached substrate, keeping rhizomes just at or slightly above the surface.
• Water thoroughly after moving, shade from strong sun for 1–2 weeks, and keep the root zone consistently moist.

Polypodium glycyrrhiza is most reliably propagated by division of its creeping rhizomes rather than from spores.

• Divide established clumps in early spring or early fall when soil is cool and moist.
• Lift or expose a section of rhizome, then cut it into pieces with at least 2–3 healthy buds and attached roots.
• Replant divisions shallowly on moist, well-drained, humus-rich substrates such as rotting wood or rocky crevices.
• Maintain high humidity and even moisture, avoiding waterlogging, until new fronds emerge and harden.

This fern is generally cold hardy in much of its native range and requires only modest winter attention outdoors.

• Tolerates light to moderate frost when rhizomes are insulated in soil, moss, or decaying wood.
• In colder areas, add a thin mulch of leaf litter over the root zone, keeping frond bases mostly uncovered.
• Container-grown plants in USDA zones colder than the local native range should be moved to a cool, frost-free, bright shelter.