Native Plants for Georgia Part II: Ferns (B 987-2) University of Georgia Extension There are about 12,000 species of ferns in the world today. Most are found in the tropics. Currently, Georgia is home to 36 genera, 119 species and 12 hybrid ferns. The list is constantly expanding as new plants are found. To grow ferns successfully, it is important to match the site characteristics and growing environment with the native requirements of the fern species you intend to grow. Even if a fern is native to Georgia, it may not be native to the area of the state where you live. 2017-03-27 15:18:55.907 2009-09-14 10:20:35.0 Native Plants for Georgia Part II: Ferns | Publications | UGA Extension Skip to content

Native Plants for Georgia Part II: Ferns (B 987-2)

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By Gary Wade, Ph.D., Extension Horticulturist (Retired); Elaine Nash, Naturalist; Ed McDowell, Master Gardener, Amateur Botanist and Wildflower Photographer; Tom Goforth, Native Fern Horticulturist and Ecological Researcher; Brenda Beckham, Master Gardener and Plant Enthusiast; Sharlys Crisafulli, Horticulture Program Assistant

Reviewed by Bodie Pennisi, Extension Floriculture Specialist

Our native landscape is the inspiration for this guide to native plants for Georgia gardens.

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"A thing is right if it tends to preserve the beauty, integrity and stability of the biotic community; it is wrong when it tends otherwise." —Aldo Leopold, "The Land Ethic," A Sand County Almanac

Acknowledgments

Acknowledgement is made to the following organizations and Web sites that provided images used in this publication:

  • Bugwood Network
  • Eastern Kentucky University
  • Hardy Fern Library
  • Ogden Archive
  • Regional Water Authority
  • River to River CWMA
  • Southern Weed Science Society
  • USDA Forest Service
  • USDA-NRCS PLANTS Database

Sincere appreciation is expressed to the following individuals who also provided images of the plants described in this publication. Copyrighted images have been used with permission from the photographers and/or the organizations providing them. Any use of these images beyond this publication is discouraged and will require permission from the photographers.

  • Patrick J. Alexander
  • Thomas G. Barnes
  • Ted Bodner
  • Troy Evans
  • A. Murray Evans
  • Chris Evans
  • V. Fulford
  • Tom Goforth
  • Warren D. Hauk
  • R.A. Howard
  • Ed McDowell
  • Jeff McMillian
  • James H. Miller
  • Robert H. Mohlenbrock
  • Gil Nelson
  • Hugh Nourse
  • Edgar Paulton
  • J.S. Peterson
  • John Triana
  • B. Eugene Wofford

Appreciation is also expressed to Jonathan Bowman, student in the Lamar Dodd School of Art at the University of Georgia, for his artful renditions of several of the illustrations in this publication.

Lastly, the Georgia Native Plant Society is acknowledged for its continuing support of this series of publications.

Natural History of Ferns

Ferns first appeared in the fossil record more than 350 million years ago. At that time, what is now temperate Europe and North America had climate conditions that favored year-round growth; the land was low and covered by swamps and shallow seas. For millions of years, the earth was dominated by cycads, ginkgos, conifers and seedless vascular plants, including ferns, lycophytes (lycopodias and selaginellas), and bryophytes (mosses and liverworts). These plants laid down the deep coal beds we now mine for energy.

Most of the dominant tropical coal-swamp plants became extinct over time. Only the ferns and herbaceous relatives of the lycophytes -- clubmosses, selaginellas and horsetails -- continued to flourish and evolve.  Today, many of these plants appear untouched by evolution and look much like they did millions of years ago. Ferns also inhabit all of the continents except frozen Antarctica.

Having been on earth prior to the Carboniferous Period (280 to 345 million years ago), ferns have survived and evolved through a long, turbulent history of time and space; a time when continental land masses were splitting and colliding, oceans were expanding and shrinking, and phenomenal climate changes were occurring.

Ferns did not arise as a single monolithic family, but as several families or groups (see Figure 1). The royal ferns (Osmundaceae) and the filmy ferns (Hymenophyllaceae) existed 210 million years ago, according to fossil records. Interrupted fern (Osmunda claytoniana), which currently grows only in eastern North America, is known to have existed 206 million years ago. Other families, including the spleenworts (Aspleniaceae), chain ferns (Blechnaceae), wood ferns (Dryopteridaceae) and polypodies (Polypodiaceae) are much younger, with fossilized records dating to the Cretaceous Period, about 75 million years ago. Sensitive fern (Onoclea sensibilis), found in eastern North America and eastern Asia, existed during the early Tertiary Period, about 55 million years ago. Many other fern families are no more than 2 to 3 million years old, and a few species, like log fern (Dryopteris celsa), are of recent origin – only 18,000 years old .

chart showing evolutionof plants and time periods based on fossils. The fern branch starts in the Paleozoic period, 350 million years ago. Figure 1. Evolutionary tree of the Major Groups of Land Plants. From R. Moran, 2004, A Natural History of Ferns.
(Redrawn by Angela Rowell, UGA, CAES Office of Communications)

Some closely related fern species are widely distributed around the earth, yet great distances separate them. One explanation for this is the continental drift that occurred at least once during the past 150 million years. As land masses separated and collided, fern species colonized new areas. A second explanation for this widespread distribution is long-distance spore dispersal. Ferns produce millions of spores that, when ripe, are ejected or catapulted into the surrounding air. Their dust-like particle size can be easily picked up by the wind and transported enormous distances in the earth’s upper atmosphere and jet stream. Experiments have shown that fern spores can tolerate the cold temperatures and intense ultraviolet radiation present in the upper earth’s atmosphere.

There are about 12,000 species of ferns in the world today. Most are found in the tropics. Currently, Georgia is home to 36 genera, 119 species and 12 hybrid ferns. The list is constantly expanding as new plants are found.

Fern Allies

Lycophytes, horsetails and whisk ferns are often referred to as “fern allies,” because they generally don’t resemble ferns, but do have some similarities. Lycophytes, which include Quillworts (Isoetes), Spikemosses (Selaginella) and Clubmosses (Lycopodium), are less closely related to ferns and are more closely related to an ancestral plant that is not shared by the ferns. Ferns and seed plants are more closely related to each other than either is to the lycophytes (see Figure 1).

On the other hand, fossil records and DNA analysis have revealed that horsetails (Equisetum) and whisk ferns (Psilotum and Tmesipteris) ARE ferns, even though they don’t resemble ferns. Whisk ferns consist of leafless branches and slender, creeping rhizomes, but no roots. They are one of the simplest and most unique vascular plants on earth.

Ten species of clubmosses, seven species of spikemosses, two species of horsetails and one species of whiskfern are native to Georgia. However, they are difficult to grow and are not good candidates for culture by the average gardener. Therefore, they are not described in this publication.

Fern Life Cycle

The fern life cycle involves two distinctly different stages: the sporophyte stage and the gametophyte stage (see Figure 2). The sporophyte stage begins with a zygote.  In the sporophyte stage, the young sporophyte has roots, stems and leaves like other vascular plants. The spore-bearing fertile fronds are called sporophylls. On their underside are borne clusters of sporangia, called sori. The cells within the walls of the sporangia become spore mother cells. These cells undergo a genetic process called reduction division with each spore mother cell splitting into four meiospores. When mature, the sporangia burst open and the spores are shot into the air. A single fern can release millions of dust-like spores that may be carried some distance by air currents before landing. If the environment where a spore lands is favorable, a spore will germinate and grow into a small heart-shaped gametophyte plant that is usually less than 1/4-inch across. The leaf-like gametophyte contains chlorophyll and makes its own food. On the underside of the gametophyte, hair-like growths aid in absorption. Near the point in the heart-shaped gametophyte are borne antheridia (male parts), and near the notch in the gametophyte are clusters of archegonia (female parts). Fertilization occurs when a sperm from an antheridium unites with an egg from an archegonium to form a zygote. The zygote germinates and grows into a young fern plant, and the life cycle starts again.

Fern life cycle. Sporophyte stage: Zygote to fern prothallium with young sporophyte to sporophyll to sporangium to spore mother cell. Gametophyte stage: Reduction division to Mesospores to prothallium (gametophyte) to archegonium to egg and antheridium to sperm then to fertilization. Figure 2. Fern life cycle. From Greulach, Botany Made Simple.
(Redrawn by Jonathan Bowman)

Identifying Ferns

Unlike many other vascular plants, ferns do not have aerial stems. The leaves arise from an underground stem, called a rhizome. The entire fern leaf is called a frond. The frond consists of the stipe and the blade. The continuation of the stipe to which the leaves are attached is called the rachis. A leaflet is called a pinna (plural, pinnae). A division of a pinna is called a pinnule. See Figure 3 and the glossary for more detailed descriptions.

Drawing of ferm showing frond (leaf), which is made up of the blade and stipe, rhizome (stem), roots, and crosier. The blade is made up of the rachis, pinnule (segment), pinna, and pinna rachis. Figure 3. Parts of a fern. From Mickel, Ferns for American Gardens.
(Redrawn by Jonathan Bowman)

One characteristic used to identify ferns is the structure of the frond, and the level to which a frond is divided (See Figure 4). Frond structure ranges from simple (the blade is undivided) to compound (the blade is divided into smaller parts). A common blade structure, called pinnate, produces pinnae (singular pinna) that are attached to an elongated rachis. Each pinna may be again divided to become bipinnate or tripinnate. Leaf blades that are deeply lobed but not fully divided into individual segments are said to be pinnatifid. When the first level of blade arrangement is pinnate and the second pinnatifid, the leaf is called pinnate-pinnatifid. When both levels of blade arrangement are pinnatifid, the frond structure is called bipinnatifid.

Illustrations showing simple, pinnatifid, pinnate, pinnate-pinnatifid, binnate, bipinnatifid, bipinnate-pinnatifid, and tripinnate structures. Figure 4. Fern frond structures. From Mickel, Ferns for American Gardens.(Redrawn by Jonathan Bowman)

In some ferns, the sterile and fertile fronds may appear distinctly different. Others have fronds that are dimorphic, which means they have two different leaf forms on the same frond (Figure 5). These are other characteristics used to describe and identify ferns.

Illustrations of dimorphic fronds: Osmunda. cinnamomea, Osmunda. claytonia, and Osmunda. regalis. Figure 5. Examples of dimorphic fern fronds. From Mickel, Ferns for American Gardens.
(Redrawn by Jonathan Bowman)

Ferns are further described according to the habit of their rhizome (Figure 6). Some ferns have a long-creeping rhizome, others a short-creeping rhizome, and still others an ascending rhizome.

Illustrations showing long-creeping rhizome, short-creeping rhizome, and ascending rhizome habits. Figure 6. Rhizome habits. From Mickel, Ferns for American Gardens.
(Redrawn by Jonathan Bowman)

Fertile fronds contain spore-bearing sporangia arranged in clusters called sori (singular sorus). In many ferns, each sorus is covered by a thin membrane called an indusium (plural indusia). In others, an indusium is not present. There are some fern species in which the sori are not covered by a true indusium but have their sori located beneath in-rolled margins of the fronds. This is called a false indusium. The presence or absence of indusia and the structure of the indusia are further characteristics used to identify and describe ferns.

Illustrations showing cup-shaped, kidney-shaped, marginal false, and round indusia. Figure 7. Examples of indusia. Drawings by Anna Stone from Palmer, 2003, Hawaii's Ferns and Fern Allies.

Gardening with Ferns in Georgia

To grow ferns successfully, it is important to match the site characteristics and growing environment with the native requirements of the fern species you intend to grow. Even if a fern is native to Georgia, it may not be native to the area of the state where you live. In order to successfully grow ferns outside their native habitat, you must try to simulate the soil conditions and climate in which they are found in nature. The vast majority of native ferns need soils high in organic matter with moderate moisture retention. Except for rugged areas in the mountains and perennial wetlands, most land in Georgia has been farmed, making the soils and growing environment less suitable for ferns. 

Native ferns offer a wide diversity of sizes, growth habits, forms, and niches for gardens. They provide a unifying element to the woodland garden, weaving their green fronds over the forest floor. In late summer, their rich green fronds add life to the forest as other plants fade and drop their leaves. A woodland garden looks incomplete without ferns.

Most ferns have three basic growing requirements: shade, moisture, and loose, well-drained soil high in organic matter.

Shade

Nearly all ferns prefer filtered shade -- the type cast by tall trees with pruned limbs. Filtered shade can also be obtained by planting on the northeast side of a building where shade is cast by the building most of the day or in courtyards shaded by surrounding buildings. North-facing slopes, as well as walls and fences with north/south orientations that cast shade during the afternoon also offer filtered shade. Protection from the hot afternoon sun and drying winds is essential. Ferns generally do not like dense shade created by thick forest canopies where little light reaches the forest floor. In the wild, ferns thrive in an open forest or near the edges of forests where light penetrates but is filtered by foliage.

Moisture

In the wild, ferns are found in a variety of habitats, most of which are moist. Adding organic matter to the planting area, planting in depressions where moisture drains, or providing drip irrigation are ways to make the growing environment more suitable for ferns. A natural way to trap moisture in an area is to allow large woody debris, like logs or large limbs, to rot in place when they fall. As they decompose, they act as natural water reservoirs, trapping rain and holding onto it like a sponge.

Newly planted ferns need to be watered thoroughly and repeatedly during establishment to maintain an adequate moisture level. The root system may take up to two years to get fully established, so supplemental moisture may be needed during periods of limited rainfall. Tree roots compete with ferns for water and nutrients, so when ferns are planted under trees, supplemental irrigation will be necessary.

Soil

Ferns need well-drained soil enriched with organic matter like compost. Heavy clay soils or soils with little organic matter do not have adequate pore space for sufficient root growth. Clay soil is not suitable unless it is amended with compost, rotted wood chips, and/or some type of aggregate to improve its structure and texture.

Ferns have a wide preference for soil pH (a measure of the soil acidity or alkalinity level). Soil pH can be determined by a soil test -- available for a nominal fee through your local county Extension office. Some species are restricted to acidic soil (pH 4.7–5.5), some prefer a more neutral pH (pH 6.6–7.2), while others grow over a wide range (pH 4.7–7.2). A few ferns that require an alkaline pH (above 7.0) and need calcium grow on limestone rocks or in soils amended with lime. Some ferns must grow on rocks or boulders that provide a cool, moist surface and crevices for their rhizomes (creeping underground roots).

Ferns to Avoid

Japanese climbing fern (Lygodium japonicum), old world climbing fern (Lygodium macrophyllum) and Marianna maiden fern (Macrothelypteris torressiana) are non-native ferns that have escaped cultivation and become invasive. Avoid planting these ferns. In this publication, Carolina mosquitofern (Azolla caroliniana) and bracken fern (Pteridium aquilinum) are described because they are native ferns; however, Carolina mosquitofern is invasive in aquatic environments and bracken fern is poisonous, so neither fern is recommended for culture.

Guide to Plant Descriptions

The native ferns described in this publication may not all be worthy of landscape culture, but most are. Some are described for the historical role they played in agriculture. Others with known invasive or other undesirable qualities are described for information purposes only. Still others may be difficult to cultivate without precise simulation of their native growing environment, but they are of botanical interest. Some ferns may be difficult to find in the nursery trade, but descriptions of their qualities may prompt a few astute growers to begin growing them and offering them for sale. Rare or endangered species of ferns are not described, and collecting them from the wild, except during organized plant rescues, is discouraged.

Ferns in this publication are grouped according to family and alphabetized, by scientific name, within the family. The description of each fern follows this format:

Common name(s) / Botanical name:

Generally accepted scientific and common names used by specialists in the field. The ancient ancestry and evolution of ferns has resulted in a great deal of disagreement among botanists as to the family and genus to which many ferns belong. In this publication, Flora of the Carolinas, Virginia, Georgia, northern Florida, and Surrounding Areas by Alan S. Weakley was used as the authority on fern classification. (http://www.herbarium.unc.edu/WeakleyFlora_2008-Apr.pdf)

Characteristics:

This category provides identifying characteristics, including information about the frond shape, the size, shape and arrangement of the pinnae, stipe shape and length, as well as the size and shape of the sori and indusia. To become familiar with these terms, review figures 3 through 7 and the glossary at the end of this publication.

Landscape uses:

Suggestions are made for using the plant effectively in the landscape. To grow native ferns successfully, it is important to simulate their native growing environment and to follow appropriate cultural management practices to provide their growing requirements.

Size:

This is an indication of mature plant size, not the size of an individual frond. Some ferns grow in colonies with spreading rhizomes, so plant size will vary with plant age and is influenced by the growing environment.

Zones:

This refers to the U.S. cold-hardiness zones to which the fern is adapted or found growing in its native habitat. The average winter temperature of the region in which they are to be grown influences which ferns can be grown successfully in your area. The USDA plant hardiness zones in Georgia are shown in Figure 8.

Georgia plant hardiness zone map
Figure 8. Cold-Hardiness Zones in Georgia
Average annual minimum temperature ranges
Zone Range in degrees Fahrenheit
6b -5 to 0
7a 0 to 5
7b 5 to 10
8a 10 to 15
8b 15 to 20

Habitat:

A description of the type of growing environment where the fern is found in the wild.

Native to:

The broad geographic area where the plant naturally occurs. Georgia has three geographical regions: Mountains, Piedmont, and Coastal Plain. Plant distribution is sometimes described in terms of these geographical regions.

Comments:

Additional noteworthy information about the plant.

The Spleenwort Family -- Aspleniaceae

The spleenworts are a large genus of small, culturally challenging, promiscuous ferns, mostly suited for moist, shaded rock gardens. While most are tropical epiphytes in this hemisphere, the temperate species grow mostly in sandstone, limestone, or granite rock crevices.

Fifteen spleenwort species and several hybrids are native to Georgia. Most are either rare or endangered. Four of the most common species in Georgia are described here.

Mountain Spleenwort / Asplenium montanum

Characteristics:

Fronds are numerous, drooping, delicate, bluish-green, and evergreen. There are four to seven pairs of pinnae on short stalks. They are pinnate at the base of the rachis and pinnatifid at the top of the rachis. The rachis is broad, green, flat, and winged at the apex. The rhizome is short-creeping, dark, and wiry, often obscured by old stipe bases. The stipe is 3/4-inch to 2 inches long, brown below and green above.

Landscape uses:

Mountain spleenwort is always associated with rocks, growing next to or tucked tightly into non-calcareous rock crevices. Use this small, delicate plant in a shaded rock garden.

Size:

3 to 5 inches high

Zones:

4 to 7

Habitat:

Acidic soils in shaded, non-calcareous rock crevices

Native to:

North Georgia Mountains, northward into Ohio and Massachusetts

Comments:

Slugs can be a problem. Mountain spleenwort is somewhat difficult to cultivate due to its requirement for a rocky environment.

drawing of asplenium montanum plant parts N.L. Britton and A. Brown, USDA-NRCS PLANTS Database
photo of asplenium montanum Troy Evans, Eastern Kentucky University, Bugwood.org
photo of asplenium montanum Tom Goforth

Ebony Spleenwort / Asplenium platyneuron

Characteristics:

Slender, pinnate fronds are either fertile or sterile. Fertile fronds arise from the center of the plant. They are erect and remain green late into the season. The arching, evergreen sterile fronds are shorter than the fertile fronds, and they are spreading, flat, and have light-green pinnae. The stipe and rachis are deep reddish brown to black. The rootstock is short-creeping.

Landscape uses:

Ebony spleenwort is the most adaptable and easy to cultivate of this genus, growing equally well on red clay banks, disturbed or open woodlands, dry forests, or in rock crevices. It is adaptable to either acidic or calcareous soils, provided they are welldrained.

Size:

10 to 18 inches high and slowly spreading to a 6-inch clump

Zones:

4 to 8

Habitat:

Disturbed or open woodlands and rock crevices

Native to:

All of Georgia, except the southeastern Coastal Plain. It ranges from Maine to Michigan, south to Texas and Florida.

Comments:

One of the most widely available spleenworts in the trade. It is sensitive to overwatering. Slugs can be a problem.

drawing of asplenium platyneuron plant parts N.L. Britton and A. Brown, USDA-NRCS PLANTS Database
photo of asplenium platyneuron Ed McDowell

photo of asplenium platyneuron Ted Bodner, Southern Weed Science Society, Bugwood.org
photo of asplenium platyneuron Tom Goforth
close-up photo of asplenium platyneuron sori Sori on fertile frond. Patrick J. Alexander, USDA-NRCS PLANTS Database

Black-Stemmed Spleenwort / Asplenium resiliens

Characteristics:

Fronds are slender, leathery, and dark green with a short stipe. Pinnae are opposite, oblong in shape with blunt tips, and smooth margins. The stipe and rachis are black and shiny.

Landscape uses:

Use this fern in a shady, moist, calcium-rich environment. Tuck it into pockets between limestone slabs or rocks.

Size:

6 to 12 inches high and 6 inches wide

Zones:

6 to 9

Habitat:

Crevices in shaded calcareous rocks

Native to:

Subtropical America, northward to Arizona, east to Missouri and southern Pennsylvania. Found in limestone valleys of northwestern Georgia and also in the Coastal Plain.

Comments:

Black-stemmed spleenwort resembles maidenhair spleenwort (A. trichomanes) in appearance but is slightly larger. Slugs can be a problem.

Status and Revision History
Published on Sep 14, 2009
Reviewed on Aug 1, 2012
Reviewed on Oct 25, 2015