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or just about any other place where concrete consumes

the dirt and skyscrapers shield the sunshine.- USA Today

 
 

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Plant Profiles

Ostrich Fern

Matteuccia struthiopteris B 021416 640

 

Emperor penguins hatch their eggs during the Winters of inland Antarctica—could there be a harsher environment?—and return to the life of the shoreline only in Spring. Above, the fertile fronds of ostrich fern. They, too, stand tall through Winter's worst, and await the return of Spring to release their spores.

 

My fingertips are numb with cold, but these fronds of Matteuccia struthiopteris are unaffected even by Winters that are literally Arctic. Gardening in Alaska or Siberia? Want a lush garden to ornament your caribou ranch? Ostrich fern thrives in cold climates around the globe. It also thrives in near-tropics. Few plants are as versatile.

 

While the feathery green fronds that emerge in Spring are notoriously fragile—and succumb to even mild frosts in Fall—the Winter fronds of ostrich fern are cold-proof because their moisture content is so low. There is too much structural material (hence these frond's near-woody rigidity) encasing too few molecules of water to join together to form ice.

 

Matteuccia struthiopteris 021416 640 

 

Without sufficient moisture for ice, there's none for the typical activities of warm weather, either: photosynthesis or water absorbtion from the roots. So these fronds lack chlorophyll and the green color it would provide. Instead, the bottom edge of each of the stiff specialized leaflets is lined with spore cases that are held in place regardless of snow or ice or high winds.

 

With the return of Spring, temperatures that are above-freezing for long enough will enable liquid water to come into contact with the spore cases long enough for them to absorb it and swell open. Because spores have been held above ground by the still-rigid fronds, when released they have the best chance of catching the breezes and drifting that much farther from the mother ship. Ostrich fern spreads by underground runners as well as by spores. One way or another, even a single clump in congenial circumstances can form a large colony that is dramatic year-round.

 

 

Here's how to grow this eccentric and indomitable native:

 

Latin Name

Matteuccia struthiopteris. Also known as Matteuccia pensylvanica, Matteuccia struthiopteris var. pensylvanica, Onoclea struthiopteris, and O. struthiopteris var. pensylvanica.

Common Name

Ostrich fern.

Family

Onocleaceae, the Sensitive Fern family. Still classified in the Dryopteridaceae family by the US Department of Agriculture.

What kind of plant is it?

Hardy deciduous fern.

Hardiness

Zones 3a to 9b. 

Habit

Each Spring, tight curls of excitingly high and feathery green sterile fronds emerge from a black crown that, over time, becomes the size of a fist. As as result, an individual Matteuccia struthiopteris clump looks like a giant green shuttlecock. Because the crown also sends out stolons that send up new crowns, even a single starter plant can mature to a dense and, eventually, widespread colony. Beginning in mid-Summer, shorter fertile fronds emerge at the very center of each crown's sheaf of sterile fronds. They are stiff and, as they mature, turn dark brown. While the sterile fronds can go downhill by August if the weather is dry—and are slain by the first frost, anyway—the fertile fronds are uniquely persistent. They are rarely damaged or discolored even by severe Winter cold, snow, and ice, and remain ebony-colored and erect until Spring, when (finally) they release their spores. Ostrich fern is a year-round garden presence.

 

In addition to the stolons, crowns send out profuse fibrous roots that knit together into thick and, in time, far-reaching mats. If you purchase rigid dark-brown fibrous blocks on which to grow epiphytic orchids, they might be dried sections of either Osmunda or Matteuccia roots.

Rate of Growth

Vigor is dependent on moisture, soil, and siting. In rich soil that never lacks for moisture, in a location that receives only moderate amounts of sun, ostrich fern can become aggressive. See "Where to use it" for guidance.

Size in ten years

Height varies with the amount of moisture and nutrients the clumps can access. When located in cool-Summer climates, and growing in rich soil that is downright moist or even boggy in Spring, and never less than moist the rest of the year, fronds can top five feet. In more typical garden conditions—average soil and water in part or full shade—expect fronds to be two to three feet high. There is less variance in the height of the fertile fronds: sixteen to twenty-four inches. In ten years, a single starter plant could expand into a colony ten feet across or more.

Texture

In warm months, the arching sterile fronds are peerlessly feathery, and flutter in the breeze. In cool and cold months, the much shorter fertile fronds are lacey but static; with their rough surface, warm rust coloring, and rigid immobility regardless of strong wind, pelting rain, or heavy snow and ice, they could have been made of Cor-Ten steel.

Grown for

its fronds: The green fronds are sterile, and can be among the longest of any fern hardier than Zone 7—to five feet—and are arrayed in graceful shuttlecock-like groups. The dark brown fertile fronds are much shorter—usually under twenty inches—and remain showy Fall through Spring.

 

its flexibility: As long as it has enough water, ostrich fern thrives in climates with bitter cold in Winter (down to minus 40 Fahrenheit) and only modestly above-freezing temperatures in Summer. It can also grow where even mild frosts are rare, and temperatures are likely to be warm year-round. If you're gardening almost anywhere but in the pure tropics and would like to establish ostrich fern in a shady and moist location, you can.

 

its fondness for cold climates: While ostrich fern thrives in both Orlando (Zone 9b) and Ottawa (Zone 3a), there are so many other choices for luxuriant and, simply, large ferns in warmer climates that Matteuccia is most striking in the cold ones. The options are far fewer there, and the cool summers are more likely to foster the moist conditions that enable the fern fronds to reach maximum size and also stay fresh through the Summer.

 

its year-round display: Thanks to its uniquely persistent and showy fertile fronds, the fern's display is only changed, not destroyed, by the slaying of the green sterile fronds by the first frosts of Fall. Even in Spring, when the fertile fronds are at last releasing their spores and falling away, the black fist-like crowns enjoy their own spare display briefly before the fiddleheads of the year's new crop of sterile fronds emerge from their tops.

 

its edible fiddleheads: In Spring, the tip of each emerging sterile frond remains tightly coiled in a spiral. As long as some are left to mature, they can be harvested as an early-season green. Along with asparagus, rhubarb, dandelions, and ramps, Matteuccia, then, is one of the small group of hardy perennial vegetables.

 

its resistance to browsers: As is typical for ferns, the mature fronds are not of interest to browsers. Given that the fiddleheads—the young fronds that are still tightly furled—are a delicious early-season treat for humans, are they also of interest to browsers?

 

its creation of seasonal animal habitat: In Spring and Summer, Matteuccia can create thick colonies of arching sterile fronds that shield animals from view of aerial predators while also extending the area of moist ground that amphibians in particular would welcome. Do frogs and toads a favor, then, by planting ostrich ferns.

Flowering season

Ferns form spores instead of seeds, and the spore cases that bear them can be showy as well as seasonal. Most ferns bear spore cases on all of their fronds; some, such as Matteuccia, bear spores only on fertile fronds. The fertile fronds of Matteuccia are exceptionally prominent and persistent. A new crop emerges annually in mid-Summer. The color deepens to ebony over the Summer but the display is somewhat hidden by the much larger sterile fronds. After these have collapsed in the first cold weather of Fall—or have been cut back by you whenever they have begun to fade in late Summer—the fertile fronds are fully exposed.

 

They do not release their spores until the following Spring and, because spore distribution is by wind, the fronds need to be so tough and well-anchored that they remain erect month after month during Fall and Winter. But in the cold-Winter climates that Matteuccia prefers, the roughest weather of the year occurs during those same months. No wonder fertile fronds are so durable. The "fruiting" season of ostrich fern, then, extends from mid-Summer of one year into Spring of the next: eight to ten months. This is extraordinarily and possibly uniquely long for any plant anywhere near as hardy.

Color combinations

The green sterile fronds go with everything. When they are prominent from late Spring through early Fall, ostrich fern is a neutral color but a striking texture. From Fall through early Spring, the fertile fronds are fully exposed; their striking dark color could be incorporated into a larger Winter garden palette focusing on copper and orange. See "Plant partners," below. 

Plant partners

Because the green sterile fronds go with all other colors, they are instead combined on the basis of size and texture. Leaves of any size, borne by plants of any height, are most effective with Matteuccia when they have comparatively simple shapes and have smooth or, best of all, shiny surfaces. Matteuccia colonies can grow thickly enough that direct underplantings can be shaded out, but that still leaves plenty of possibilities for partners to the front (vinca, smaller hostas, carex, & hakonechloa), the sides (rodgersia, large hostas, rhodies, & inkberry), and the rear (big-leaf bamboo if you can keep it and the fern apart, larger rhodies and hollies if you can't).

 

Although Matteuccia will thrive in full sun when growing in rich soil that never dries out, it's more often that this fern will receive some shade from larger shrubs as well as trees. If circumstances permit, perhaps the most exciting pairing is for ostrich ferns to grow on the north and east sides of a southern magnolia; the magnolia's large, evergreen smooth-edged, deep-green, and extraordinarily shiny foliage couldn't be a better foil for both the fern's sterile and fertile fronds. If the ferns are able to colonize under the magnolia's drip-line, all the better, but when growing in soil with normal moisture, magnolia will not usually permit that.

 

Because the fertile fronds' display lasts Fall through Spring, shade-providing partners with particular Winter displays are always welcome. Consider forms of Cornus mas, Corylopsis, HamamelisLindera, and, if your climate is at least as mild as Zone 7, Edgeworthia. Consider also Winter and early-Spring plants such as Eranthis, Galanthus, and Helleborus.

 

The unusual cinnamon and ebony of the fertile fronds in Winter might tempt you to a surrounding display of plants featuring orange and copper. See the discussion of "Plant partners" for Tilia cordata 'Winter Orange'.

Where to use it in your garden

Matteuccia is most massive and visually exciting when growing in supportive conditions—see "Culture," below—but these are just the conditions that also ramp up the species' outward-bound aspirations. And while spread could be contained by in-ground barriers, somewhat in the way you'd contain bamboo, these are more likely to be heaved by the moist soil and deep freezes that Matteuccia prefers. But restraining the expanse of a colony by tying fronds back or by limiting the roots with paving or mown grass are all problematic; see "Downsides," below.

 

Instead, plant ostrich fern where it has plenty of room to spread. Control it by bordering with the fresh water of a pond, bog, or stream; ledge or masonry walls; extensive aprons of groundcovers into which it can spread at will or banks of large dense shrubs that will frustrate or at least hide its incursions; or by having the soil of abutting beds be so lean and unable to retain moisture that Matteuccia roots and runners can't colonize it.

 

Matteuccia is thrilling in sweeps in naturalistic settings such as open woodland, pond- or stream-side, or in damp pockets at the base of ledge. It is unsuited for in-ground beds in compact gardens, or urban gardens in general, because their beds are usually bordered either by paving or by grass. Its deep hardiness also makes it possible for use in permanent containers, which would handily control its spread. See both "How to handle it" boxes, below.

Culture

Matteuccia thrives in soil of average fertility and moisture if it receives enough shade: One of my most vigorous indigenous colonies is growing in well-drained soil between my contorted beech and a full-to-the-ground espalier of 'Winter Orange' lindens just a few feet away. Growth is even more enthusiastic when the soil is never less than moist and the shade is high and open, as would occur beneath deciduous trees in open woodland. For possibilities, see "Where to use it," above, and "Quirks," below.

 

While the sterile fronds are produced even in dense shade, dappled sun is usually necessary for production of fertile fronds. 

How to handle it: The Basics

Plant in Spring or Fall, ensuring enough water for establishment. If your site supplies enough water for ongoing growth, you need do little thereafter, even year after year, other than (if you want) cutting down the sterile fronds after they have been hit by frost. You could also do this in late Summer if conditions have been so hot and dry such that these fronds have become tattered even before frost. The goal in removing them is to concentrate the cool-season display around the erect fertile fronds.

 

The "fertiles" remain showy through the Winter into Spring, when they release their spores. If you think of it, clip them off before the fiddleheads of the new crop of sterile fronds get in the way. Or you can forget to do this, confident that the sterile fronds will hide the old fertiles soon enough.

 

Matteuccia colonies don't need division to retain vigor, but they may well need control around the perimeter if they aren't to keep spreading indefinitely. Chop into the perimeter of the colony with a spade any time the soil is workable when the fluffy, overhanging, and fragile sterile fronds are not present. It would be maddening to attempt to dig around the colony when they are: You wouldn't be able to avoid snapping some of the "steriles."

How to handle it: Another option—or two? 

Matteuccia is extremely hardy, and its displays of sterile and fertile fronds ensure that it has presence year-round. Why not grow it in a permanent container? That would also control its otherwise persistent interest in spreading.

 

But what container? It would need to be "hardy" as well to survive years outdoors, fully planted, in the cold climates Matteuccia usually prefers. And it would need to be filled with moisture-retentive soil but still provide just a bit of drainage: Matteuccia is not an aquatic plant, and enjoys standing water only when in active growth in Spring.

 

The easiest choice would be a galvanized ten-gallon washtub. It you have a large enough ledge or wall to set it atop (the washtub would eventually warp or even fail if only a portion of its bottom rim were supported), you could enjoy the cold-season displays of fertile fronds and black crowns close-at-hand. (I needed to kneel in the snow to take the pictures for this post.)

 

It is easy to drill a couple of small drainage holes in the bottom, and the tub should maintain its integrity for five years or so. Be sure to water liberally in the warm months; siting the tub in part shade is probably the wisest choice to reduce the chances of a serious dry-out during Summer.

Quirks and special cases

Matteuccia is usually marketed as tolerating wet ground, but the fern tolerates standing water only briefly, and only in Spring as a result of the late-Winter thaw and often heavy Spring rains. The fern is reported to have better tolerance of inundation when such high water is also in motion, as would be the case on the banks of streams. There the spreading, thick, and mat-forming roots also help control erosion.  

 

In locations where standing water from seasonal flooding is typical in seasons other than Spring, cinnamon fern, Osmundastrum cinnamomeum, provides a similar look and bulk but with greater tolerance of saturated soil. This is the fern, then, for the bottom of the basin of a rain garden that regularly "pools up." Matteuccia would be better when planted no lower than the basin's rim.

Downsides

While the fertile fronds would only be damaged by direct assault—stepping on them, say—the sterile fronds are frustratingly fragile. Plus, their surface and texture is just tactile enough that, in mass plantings, the fronds of one clump can tangle with those of its neighbors if you were to attempt passage amond them, or restrain a colony whose foliage is billowing out of bounds. Further, the frond's stem is brittle, and is more likely to kink permanently than to bend resiliently.

 

Do not site ostrich fern where its fronds will overhang paving; they don't tolerate being brushed by passing legs. Don't site ostrich fern alongside lawn, either, because the regular passage of lawn mowers will also inevitably damage overhanging fronds.

Variants

M. struthiopteris 'The King' can grow much taller than the species—reportedly to seven or even eight feet in ideally moist sites in cool-Summer climates. It is also more tolerant of high heat and warm nights, so thrives farther south. It is worth growing instead of the species anywhere; if you are gardening in Virginia, North Carolina, and the upland portions of South Carolina, 'The King' is likely to be the form of ostrich fern that will do best.

Availability

Online as well as at retailers.

Propagation

By division in late Winter or Spring, before the somewhat fragile new sterile fronds begin appearing, or anytime in late Summer or Fall after they have been hit by frost. Individual crowns are not usually divisible, but stolons form new crowns readily when moisture is plentiful. With a sharp spade, chop vertically around each crown to sever it from what can be a thick mat of surrounding roots that service it as well as other crowns. 

 

If you can provide enough water, or the fern is growing in dappled shade or, even, full shade from mid-morning to late afternoon, you can divide colonies or transplant crowns at any time, even the height of Summer. Cut back all the full-size fronds by half; the mere process of digging up established clumps will inevitably snap many of them anyway. Water the replanted divisions copiously for a few weeks to be certain they have enough moisture to establish. At the center of each crown, new fronds will attempt to unfurl almost immediately if there's enough water; the quicker they grow, the more energy the divisions can make use of in re-establishing. You can help things along for the first few weeks by covering each transplanted crown with shade cloth or that floating gauzy stuff (Remay is one brand) that's intended to keep bugs (or early or late frosts) away from rows of vegetables.

Native habitat

Matteuccia struthiopteris is broadly native to almost all of North America east of the Rockies where Winter temperatures are likely to fall at least into the twenties and teens Fahrenheit and, preferably, much lower: from North Carolina west to Missouri and Nebraska, all states north and east of them, Canadian provinces from Labrador to the Yukon, to all of Alaska. The fern is also indigenous to cold-Winter areas of Europe and Asia. Chances are that, in the northern hemisphere, if a typical Winter brings enough snow such that you'll sometimes need to shovel it because it won't melt on its own in a couple of days, ostrich fern is native.

 

Unaccountably named for a 19th-Century Italian physicist Carlo Matteucci. Not a botanist at all, Matteucci researched bioelectricity, the electrical currents that are created as part of the normal functioning of nerves. Struthiopteris is also eccentric, but at least it's germaine: Struthio is Greek for ostrich, while pterion means wing. Both the fertile and sterile fronds of this fern have a more-than-passing resemblance to feathers.

 
 
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