The Stately Royal Fern

Royal Fern (Osmunda regalis)

Who does not know
That those famed caves, on Arran's western shore,
Were King's Coves called, because they shelter gave
To Scotland's bravest King in hour of need
And when we see how richly they are fringed
With royal fern, might not we almost think
This stately fern delighted still to grow
'Midst scenes once honoured by so great a prince

 -David Landsborough, Arran: A Poem

Royal ferns (Osmunda regalis - pronounced os-MUN-duh re-GAY-liss) are so named because individuals can grow to be rather large. Some specimens have been recorded up to 5 feet tall and 5 feet across. You can't miss them in the garden. Sterile fronds sprout as slender croziers in spring, yellowish green in color and lightly tinged with terra-cotta. Mature fronds are bright green. The leaves are deciduous, turning pleasing yellow in fall before becoming brown. When back-lit by the sun, the yellow fronds are distinct and beautiful.

Many gardeners struggle with wet soils. Filling in the low spots is often considered to be remedy, but the water is simply redirected somewhere else sometimes causing another problem. I recommend leaving the wet areas alone and populating them with suitable plants. The royal fern is such a plant. Because they thrive in wet soil, royal ferns are ideal in rain gardens and bog gardens, beside streams and ponds. They'll even live in standing water. Tramping outdoors, they are often found in light shade, but royal ferns can certainly tolerate full sun.

Orchid growers are familiar with royal ferns, though they may not realize it, for the dried rhizomes of royal ferns have been used as potting medium for their epiphytes. Other materials are now more often used.

Widely distributed, royal ferns can be found growing in many parts of the world. It's no surprise, then, that they are hardy in a wide range of climate zones. In North America, these perennials are hardy from USDA hardiness zone 3 to 10.

Though they can become large, mature royal ferns can be as small as 24 inches tall and as wide. Much depends upon the moisture level.

Not much soil preparation is needed. Tilling wet soil would be a futile exercise, anyway. A soil sample should be taken to your nearest Cooperative Extension Service office for analysis. Follow the instructions. Recommended soil pH is 6.0 to 7.8.

Plant bare-root ferns in mid- to late spring or fall. Container-grown ferns may be planted any time of year. Space them 24 to 48 inches apart.

Very little to no maintenance is needed. Fertilizer should not be necessary. Brown fronds may be removed in winter. Soil moisture should be maintained.

Suitable companion plants may include red maple, pond cypress, dawn redwood, myrtle-leaf holly, inkberry holly, baccharis, coastal leucothoe, elephant ear, cinnamon fern, netted chain fern, yellow water iris, jewel weed, horsetail and acorus.

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Cinnamon Fern: A Beautiful Solution

Rambling through moist woodlands of Eastern North America, you're likely to come upon Cinnamon ferns. Why they are so named is not known precisely. The botanical name, Osmunda cinnamomea (pronounced os-MUN-duh sin-uh-MOH-mee-uh), means "fragrant, resembles cinnamon."

The Fern Bulletin, July 1907 reported, "Mrs. A. P. Taylor of Thomasville, Ga., writes that Osmunda cinnamonea glandulosa is decidedly aromatic. If bruised early in the day it is of a spicy fragrance. Mrs. Taylor suggests that this may be the origin of the name cinnamon fern, but the evidence appears to be against this." Mrs. Taylor guessed, but not well enough, apparently. The Missouri Botanical Garden website states that "the common name of this plant is in reference to the cinnamon colored fibers found near the frond bases." Though I highly respect MOBOT, that seems a bit obscure. My conjecture is that the name was derived from the tall, slender, cinnamon-colored spore-bearing fronds that appear in spring. They look like cinnamon sticks to me, and are very obvious. On the other hand, taxonomists have never been shy about referencing obscure or potentially embarrassing characteristics of plants when naming them. I suppose, though, that the only way to know for sure is to find a written record left by the naming taxonomist, or minutes of an ad hoc committee on naming this thing.

Cinnamon fern has also been known by other botanical names including Osmunda bipinnata, Osmunda cinnamomea var. cinnamomea, Osmunda imbricata, Osmundastrum cinnamomeum and Anemia bipinnata. I only mention them in passing; you needn't remember.

Cinnamon fern grows from 30 inches to 60 inches high, and as wide as it is tall. Light green fronds emerge as "fiddleheads" in spring, unfurling into a splendid display. Foliage is deciduous, turning light yellow in fall before browning. The cinnamon-colored spikes are very attractive.

The native range of Cinnamon fern is widespread. You can find it growing from the Gulf Coast counties of Texas to Southern Florida, and northward into Canada. That's from USDA Zones 2 to 10.

As I wrote earlier, you'll find it in moist woodlands. Wet to moist woodland soils may be sandy, loamy or clayey, and usually acidic because of the tannin in decomposing leaves. This fern, however, will tolerate slightly alkaline soil. Cinnamon fern thrives in light shade or partial shade, but will tolerate dense shade, too. Gardeners with sites like that often consider them to be problem areas. If you have such a site, you're actually in luck because Cinnamon fern is your solution plant, and what a beautiful solution it is.

Cinnamon fern requires little or no maintenance, and has no significant insect or disease problems. Deer and rabbits shouldn't eat it, though there's no telling what a really hungry deer will munch.

About the fiddleheads: these are probably not your edible types. That would be Ostrich fern (Matteuccia struthiopteris). Very many ferns are more or less toxic. I suppose that's what makes them unpalatable to deer and rabbits, which seem to have good sense about such things.

Before you purchase plants, get your planting site ready. Take a soil sample to your nearby Cooperative Extension Office for testing. Make soil adjustments as prescribed. Wet woodland soils shouldn't need to be cultivated. You'd get bogged down if you tried. Moisture will incorporate soil amendments into the planting area very effectively.

Plant spacing will depend on how large they may grow, and whether you want them to grow together. Planting 24 inches to 30 inches apart should be good enough.

If you purchase bare root crowns, keep them in a cool, dark area of a basement or a refrigerator.  Not wet, slightly damp.

If you purchase your ferns in pots, water the plants in the pots, then drain.  Dig planting holes into the soil a little less deep than the depth of the growing container. Place the ferns into the holes and back-fill, watering as you go. Press soil around the root balls.  If planting bare root plants, the crowns should be just above the soil surface. Don't bury them. Add a top-dressing of mulch around the plants, not on top of them, about 1 inch deep. Fertilizer probably won't be needed, but ferns tend to benefit from occasional feeding with diluted fish emulsion.

Shade gardeners and those who like to landscape with native plants should find Cinnamon fern to be very useful. Cinnamon fern is perfect for rain gardens, bog gardens, stream banks, shady ditches and, of course, moist woodlands.

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