Does it need full sun?

No, it prefers partial to full shade.

How much water does it need?

It requires consistently moist to wet soil.

Plant guide

Cinnamon fern.

Osmundastrum cinnamomeum

Pronounced os-mun-DAS-trum sin-na-mo-ME-um

Also known as Buckhorn, Cinnamon Fern

The cinnamon fern is a beautiful, hardy perennial that adds a lush, prehistoric feel to damp, shaded garden spots. It is named for the unique, cinnamon colored fertile fronds that rise from the center of the plant. These ferns are quite resilient once they get settled in the right environment.

Another photo of Cinnamon fern — Photo by Judy Gallagher (CC BY-SA) via iNaturalist

At a glance

Care level: Easy
Plant type: Fern
Light: Partial shade to full shade
Indoor light: Medium light
Water: Every 2 to 5 days
Mature size: 3 to 5 feet
Growth rate: Medium
Hardiness: USDA 3 to 9
Bloom time: Does not bloom

Care

Keep the soil consistently moist, as this fern thrives in boggy or wet conditions. Watch for browning frond tips, which often indicate the soil has dried out too much. Provide plenty of organic matter to mimic its natural woodland habitat.

Watering: Keep the soil constantly damp and never let it dry out completely.
Feeding: Apply a balanced, slow release fertilizer once during the spring.
Pruning: Trim back dead or damaged fronds in late winter or early spring before new growth begins.
Repotting: Repot only when the fern becomes root bound or outgrows its current container.
Soil: Rich, acidic, and moisture retentive soil
Soil pH: 4.5 to 6.0
Temperature: -35 to 30°C
Humidity: 60 to 90%
Drought tolerance: Low
Lifespan: Perennial, can live for many decades.
Deer and rabbits: High

Signs it needs repotting

Roots growing out of the drainage holes.
Water sitting on the surface for too long.
Plant growth slowing significantly.

Safety

People: The plant is generally considered non-toxic, but raw fiddleheads can cause digestive upset.
Children: The fuzzy hairs on the fiddleheads can be irritating if handled or rubbed into eyes.
Contact allergens: The fine, rusty hairs on the young fronds can cause mild skin irritation.
Airborne allergens: Spore release in late spring and early summer may trigger mild respiratory sensitivity in some individuals.
Edibility: The fiddleheads are not recommended for eating. They are bitter, contain tannins and potential carcinogens, and are easily confused with the edible fiddleheads of the ostrich fern.

How to identify it

Large, arching green sterile fronds
Distinctive cinnamon colored fertile spikes
Clump forming growth habit
Fuzzy brown scales on young fronds

Height: 0.6 to 1.5m
Spread: 0.6 to 1.2m
Leaves: green, cinnamon, deciduous
Flowers: 0cm

Problems to watch for

By symptom

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Growing it

Propagation: division, spores
When to plant: spring, autumn
Overwintering: Cut back the dead, brown fronds in late winter before new growth emerges. Ensure the crown stays moist but not waterlogged during the dormant season.
In containers: It grows well in large, self-watering containers that keep the soil constantly moist.

Division

1. Dig up the clump in early spring.
2. Use a sharp spade to divide the root mass.
3. Replant immediately in moist soil.

Plant these in groups to create a lush, prehistoric look in damp corners of your landscape.

Grows well with

Hosta · They share similar shade and moisture requirements.
Marsh Marigold · They both thrive in the wet soil of a bog garden.

Similar species

Ostrich Fern · It has a similar vase shape but different frond structure.

Science

Family: Osmundaceae
Genus: Osmundastrum
Order: Osmundales
Class: Polypodiopsida
Native range: Eastern North America and parts of Eastern Asia.
Conservation: It is considered a species of least concern, though it is protected in some specific states due to over-collection.

It thrives in swampy areas and along stream banks where moisture is abundant.

Value to wildlife: provides cover for small amphibians, nesting material for birds
Uses: woodland gardens, bog gardens, erosion control, shade borders

Through the year

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Flowering

Fruiting

Foliage

Ecological indicators

Salinity: 1/9
Soil reaction: 4/9
Light: 3/9
Temperature: 5/9
Moisture: 8/9
Nutrients: 4/9

Taxonomy resolved against GBIF.

Questions people ask

Does it need full sun?: No, it prefers partial to full shade.
How much water does it need?: It requires consistently moist to wet soil.

Where the name comes from

The name cinnamomeum refers to the cinnamon color of the fertile fronds.

Good to know

The common name comes from the cinnamon colored fertile fronds that appear in the center.
It is a true living fossil.
The fertile fronds are distinct from the sterile green foliage.

Also in

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This guide was generated with AI on September 26, 2026 and checked against GBIF taxonomy. It is general information, not horticultural or veterinary advice. Read about how we build these guides.