Cinnamon Fern Care: How To Grow Osmunda Cinnamomea

The Cinnamon Fern aka Osmunda cinnamomea (os-MUN-duh sin-uh-MOH-mee-uh) is an attractive fern that grows naturally in many areas of eastern Asia, North America and Canada. 

This fern is native in such far-flung locations as New Mexico, Texas, Florida, Minnesota and Labrador. It can also be found in tropical settings.

Cinnamon Fern aka Osmunda

This member of the Osmundaceae (os-MUN-DAY-see-eye) family is a hardy perennial that thrives along stream and creek sides, in bogs, swamps and other moist, shaded areas.

The plants’ genus name, Osmunda, means “fragrant“. The specific epithet, cinnamomea, is interpreted as “like cinnamon” and is a reference to the brown, fronds (fertile) of the plant, as well as the reddish-brown fibers that are found around the base of the plant.

The plants’ common name, Cinnamon Fern, is also a reference to these aspects of the plant.

Related Reading: Growing The Classic Boston Fern

Osmundastrum Cinnamomeum Care

Size & Growth

Cinnamon Ferns typically grow to be two or three feet high and wide, but in ideal conditions it can grow to be five or six feet tall.

The plants’ leaves emerge as fiddle heads from the plants’ base. Within a few days, they unfurl to become very large yellow/green, pinnately compound fronds that are sterile. 

The 2’ to 4’ foot long fronds are lime green throughout the growing season. In autumn, they turn yellow.

The sterile fronds grow in an outward bending, vase shaped circle surrounding the fertile fronds. This presents an altogether attractive and very dramatic appearance.

Flowering & Fragrance

Ferns do not have flowers, but reproduces through spores. The spore bearing sori crowd thickly onto the back of narrow, fertile leaves. 

The sporangium are cinnamon colored and appear early in the springtime.

Light & Temperature

These shade loving plants naturally prefer a wooded setting, but they can tolerate sun (even full sun) if they are standing in water. In areas with only moist or damp soil, these ferns require partial to full shade.

Cinnamon Osmunda Fern is winter hardy in USDA hardiness zones 3 through 9.

More on Full Sun Ferns

Watering & Feeding

These swamp loving plants require a great deal of water. It’s best to grow them in soil that is rich in organic compost for consistent, continuous feeding.

Soil & Transplanting

These hardy native ferns do very well in acidic wet soil that is rich in humus. Mud, sand, sandy loam, clay, clay loam and calcareous soils are all acceptable. The pH level should be 6.8.

Grooming & Maintenance

Keep your ferns healthy and strong by removing dropped and dead leaflets and fronds as needed. This will help prevent problems with fungal development while maintaining a tidy appearance.

How To Propagate Cinnamon Osmunda Fern

Cinnamon Ferns may be propagated using fresh spores or through root division. Of the two, root division is simpler and more surefire. 

This is why it is most typically used by green houses and by individual gardeners. Single ferns are simply divided into several separate ferns and then replanted.

Cinnamon Fern – Osmunda cinnamomea Pest or Diseases

This hardy, vigorously growing native plant does not have any serious disease or insect problems.

Is The Osmunda Fern Considered Toxic or Poisonous?

Cinnamon Ferns have no specific warnings of toxicity, but it is worth noting that many ferns do contain carcinogens, as well as an enzyme known as thiaminase, which depletes vitamin B levels in the body.

This enzyme can be destroyed by completely drying the plant or cooking it, so it is possible to enjoy the fiddleheads cooked as an asparagus-like native dish.

Is The Fern Considered Invasive?

This broadly distributed native plant is not invasive in the United States or Canada.

Suggested Cinnamon Fern Uses

As an ornamental Fern, Osmunda is an excellent choice to adorn wet areas surrounding streams and ponds. It does well in water gardens and in swampy areas. 

It can make a nice shaded border and is a good addition to woodland gardens and shaded wildscaping projects.

This video shows the cinnamon colored Fern in a natural, wildscaped setting.

Cinnamon Fern is tolerant of heavy shade and the presence of rabbits. It can be planted successfully under and around Black walnut trees.

The plant is very attractive to birds, who like to use the fuzzy covering of young fiddleheads as nesting material.

The Osmunda fiber is used commercially as an orchid potting medium.

The fiddleheads can be eaten raw, added to salads or sautéed with onion, garlic and butter for an asparagus like dish. 

The latent buds are also edible and can be eaten raw early in the springtime. They are said to resemble chestnuts in both flavor and appearance.

Cinnamon Fern has also been used extensively in folk medicine as a treatment for rheumatism, headaches, colds and flu and a variety of other ailments. 

It should not be used medicinally without extensive knowledge of the plant and correct methods of processing it for these purposes.

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