Growing Ferns in Iowa

Care and How To

Fern in shade gardenFerns are some of the oldest members of the plant kingdom. They are often found in shaded, damp forests in temperate and tropical areas of the world, but many have adapted themselves to survive in various environments. The ferns that will grow in Iowa range from less than 1 foot tall to more than 3 feet tall.  Ferns can be used as focal points or as background or filler plants in shady garden beds. They also are effectively used on slopes or bordering walks and drives.

Ferns pair nicely with woodland wildflowers and spring flowering bulbs. As these plants bloom early in the spring and often disappear by midsummer, they leave empty spaces for ferns to expand during the summer months. Ferns are often fine-textured perennials that also combine nicely with other more coarse-leaved plants like hosta.


Fern Anatomy | Life Cycle | Propagation | Growing Conditions | Pests & Disease | Ferns Species for Iowa


Parts of the Fern

Diagram of fern parts
Parts of a Fern

Ferns have a unique anatomy.  The rhizome grows horizontally above or below the ground.  For some species, it can grow erect.  This spreading stem produces the leaf on the top and roots on the bottom.  The entire leaf, or frond, is curled up at emergence and unrolls as it grows. The curled-up stage is referred to as a crozier or fiddlehead. Fronds may be undivided, divided, or much divided.  The leaf blade, called the lamina, is composed of pinnae which are sometimes lobed.  The stipe is the lower portion of the stalk from the base of the lamina to the top of the rhizome. The midrib of the frond to which the pinnae are attached is called the rachis. In ferns whose fronds are much divided, the branch is termed the secondary rachis. If they are divided again, it is termed a tertiary rachis.

Fern Life Cycle

The life cycle of the fern is fascinating and complex. It depends entirely on water for regeneration. If moisture is limited during the process, the immature fern will die.

Ferns experience two stages before completing their life cycle— gametophyte and sporophyte.  The gametophyte stage grows from a spore and produces both male and female gametes (an egg and sperm).  With the aid of water, the egg and sperm come together (fertilization) to form a zygote.  The sporophyte stage grows from the zygote into the attractive fronds we are familiar with that eventually produce sporangium, which releases spores and starts the cycle over again. 

Fern fronds can be fertile or infertile. Fertile fronds contain sporangium and infertile ones do not.  In some species, the fertile and infertile fronds look alike; in others, they are quite different, making their function obvious. Ferns with different fronds are known as dimorphic.

Fern Propagation

Fern sori
Spores are located in sporangium, which are clustered into sori.  Often sori are found on the back side of fertile fronds.  The size, color, shape, and pattern of sori are often used to identify ferns that otherwise look very similar.

Ferns reproduce by spores rather than seeds. The dust-like spores form in a case called a sporangium. These cluster together in groups called sori. The sori are visible to the naked eye on the underside of the fronds. Some sori form interesting patterns, shapes, or ribbons; others are random dots or lines. The location, size, pattern, color, and shape of sori are one of the most reliable features to use to help identify fern species that otherwise look similar.  As they mature, the sori turn from a green indentation to a rusty brown to an almost black raised cluster. The spores are forcibly released and carried by the wind or water at maturity. 

Because germinating spores is often difficult and time-consuming, gardeners rarely propagate ferns by spores.  It is much easier to propagate ferns through division.  Ferns with creeping rhizomes can be cut into 2- to 3-inch (5- to 8-cm) sections containing roots and shoots. After removing dead and damaged portions, replant the sections at their original level in the soil. Crown-forming ferns can be divided when the plant has grown several crowns. Strong crowns are sliced away from the parent plant using a sharp knife. Each division should contain sufficient roots and shoots for survival. Again, replant the division at its original level in the soil. Ferns can be planted at any time during the growing season in Iowa. However, late summer or early fall is the optimum time for division of most species.

Growing Conditions for Ferns

Soils

For most ferns, a soil pH between 6 and 7 is adequate. The soil should have plenty of organic matter so it is moisture-retentive but not soggy. Leaf mold, compost, peat moss, wood shavings, etc., can be used effectively to amend soils. This provides optimal growing conditions for the fern's fibrous root system.  Ferns prefer evenly moist soils that are well-drained but don’t dry out. While many ferns like moist soils, few will tolerate standing water for long periods.  When watering, water deeply and thoroughly to encourage good root development.

Mulch applied in late fall will prevent the heaving of newly planted crowns and shallow root systems. In the spring, carefully pull aside any excess mulch from the fiddleheads. Avoid using rakes or other equipment that may damage tender new growth.

Light

Fern fiddleheads
Fern fiddleheads unfurling in spring

Ferns prefer varying degrees of shade. Full sun may cause the fronds of some species to wilt and die. Strong light causes fronds to turn yellow in color and have shorter, thicker growth. Insufficient light will cause fronds to be elongated and spindly. Ferns growing in proper light will produce large fronds characteristic of the species. Protect ferns from the wind to help reduce potential damage.

Fertilization

Ferns do not require a great deal of fertilization. Adding compost, humus, or shredded leaves usually provides sufficient nutrients. Another option is to apply a balanced fertilizer, such as 10-10-10, in the spring as fiddleheads emerge. Apply one pound per 100 sq. ft. of garden area.

Pests and Diseases of Ferns

Ferns have few problems. Insect pests of ferns include leaf hoppers and caterpillars. Handpick minor insect infestations or use insecticides labeled for ferns.  Many fern species are sensitive to insecticide sprays and may suffer more damage from the insecticide than from the insect. Slugs and snails are an occasional pest of ferns. They can be controlled by hand picking and slug baits.

Diseases affecting ferns are rare, including tip blight, various leaf spots, and leaf blister. To help control diseases, remove and destroy affected fronds and allow as much air movement between plants as possible.


Fern Species for IowaFern Frond

(*Native to Iowa)

Northern Maidenhair Fern

Northern Maidenhair Fern Adiantum pedatum
Northern Maidenhair Fern (
Adiantum pedatum)

Adiantum pedatum
Hardy in zones 2 to 8     
Height 1 to 2 feet (30 to 60 cm)
Native to North America, including Iowa

The dainty maidenhair fern is native to much of the North Central and Eastern US. The wiry petiole is shiny purple-brown to dark brown with light to medium green foliage (pinnules). Evenly moist soils are necessary for successful growth. It will tolerate deep shade but does best in the dappled shade often found in the woodlands. Although it spreads by creeping rhizomes, the plant's growth is slow and it is not invasive.

Lady Fern

Athyrium filix-femina
Hardy in zones 4 to 9     
Height 1.5 to 2.5 feet (45 to 75 cm)                   
Native to North America, including Iowa

Lady ferns have a soft appearance as the result of finely divided fronds. New fiddleheads are continually sent up throughout the spring and early summer. Frond color varies with age and location from yellow-green to medium green. Lady ferns prefer partial shade and moist, neutral, to slightly acid soils.  Dozens of cultivars that vary in size and degree of dissection in the frond are available.

Japanese Painted Fern

Japanese Painted Fern Athyrium niponicum 'Pictum'
Japanese Painted Fern (
Athyrium niponicum 'Pictum')

Athyrium niponicum 'Pictum'
Hardy in zones 4 to 9     
Height 2 feet (60 cm)
Native to East Asia

The Japanese painted fern blends wine-red with gray-green to create attractively colored fronds. The pinnae, as well as the fronds, are roughly triangular in shape. Best growth is produced in neutral to slightly acid soils and partial to full shade. Too much sun will wash out the vibrant colors in the fronds.  Water thoroughly and regularly during dry periods.

Bulblet Bladder Fern

Cystopteris bulbifera
Hardy in zones 3 to 9     
Height 18 to 30 inches (45 to 75cm)                        
Native to North America

Bulblet bladder fern thrives in shade and moist neutral soil. The arching fronds are deciduous and deeply cut and often twice pinnate.  This Iowa native is especially useful near running water or pools. In addition to reproducing by spores, this fern reproduces by small pealike bulblets at the base of the pinna. These bulblets drop from the fronds when they mature and will grow into more plants that create a nice patch.

Brittle Bladder Fern

Cystopteris protusa
Hardy in zones 4 to 8        
Height 2 to 6 inches (5 to 15 cm)     
Native to North America, including Iowa

The foliage of brittle bladder fern is yellow-green and tapers at the end. It prefers a slightly acid to neutral soil with abundant moisture. Plants grow best in a shaded location. Sometimes fronds turn brown in summer but new growth greens back up again in fall.  Fiddleheads begin to appear in early spring and continue all summer.

Hay Scented Fern

Dennstaedtia punctilobula
Hardy in zones 3 to 8     
Height 1.5 to 2.5 feet (45 to 75 cm)                         
Native to North America

This fine-textured fern is much tougher than it looks.  The North American native fern easily spreads to fill in garden spaces.  Fronds are yellow=green with a red-brown stipe.  Crushed fronds smell lightly of hay.  Grow in shade to part-shade.  Plants tolerate a wide variety of soils, especially once fully established, and will tolerate drier soil conditions than most ferns but prefers a consistently moist but well-drained location.  Grows well on slopes.

Crested Wood Fern

Dryopteris cristata
Hardy in zones 3 to 7     
Height 2 to 3 feet (60 to 90 cm)                
Native to North America, including Iowa

The first fronds to appear on this Iowa native are fertile, while the latter ones are sterile. The foliage on both is dark green. Plants prefer moist, slightly acidic soil growing readily in marshy areas or near streams and ponds.  Protect fronds from strong winds. It grows best in a shaded location.

Autumn Fern

Autumn Fern Dryopteris erythrosora
Autumn Fern (
Dryopteris erythrosora)

Dryopteris erythrosora
Hardy in zones 5 to 8     
Height 1 to 2 feet (30 to 60 cm)
Native to Asia

The fronds of autumn fern emerge with a coppery-red color and fade to a glossy green by summer.  The evergreen fern has attractive bright red sori on the underside of the frond.  The triangular-shaped fronds stand well even through winter.  Plants are easy to establish, and plants slowly expand in size by short creeping rhizomes.  It grows best in loose, well-drained soils with abundant organic matter and consistent moisture. Light shade is preferred for best growth, but plants tolerate shade well.

Male Fern

Dryopteris filix-mas
Hardy in zones 4 to 8     
Height 2—3 feet (60 to 90 cm)                  
Native to North America

The male fern grows well in neutral to acid soils with abundant organic matter and moisture. This crown-forming fern has nearly evergreen leaves. A new flush of foliage is produced each spring. Plants prefer shaded locations but will tolerate more sun if provided abundant moisture.  Protect from strong winds.

Goldie's Fern

Dryopteris goldiana
Hardy in zones 3 to 8     
Height 3 to 4 feet (90 to 120 cm)                              
Native to North America, including Iowa

Also sometimes called giant wood fern, Goldie's fern is native to parts of Iowa and is one of the largest ferns grown in Iowa. The dark, green leathery leaves can be up to 48 inches long (120 cm.). A crown of next year's fiddleheads form in late summer and early fall. Despite its large size, this fern is deciduous. Goldie's fern requires moist, cool, shady locations for best growth.

Marginal Wood Fern Dryopteris marginalis
Marginal Wood Fern (
Dryopteris marginalis)

Marginal Wood Fern

Dryopteris marginalis
Hardy in zones 3 to 8     
Height 1 to 2 feet (30 to 60 cm)                
Native to North America, including Iowa

Also called leather wood fern, the foliage of marginal wood fern is light yellow-green, changing to blue-green as it matures. This fern is evergreen and native to parts of Iowa. In late summer, it forms a crown of tightly closed fiddleheads that is partially exposed. Because it is crown forming, marginal wood fern does not readily spread. It grows best in loose, well-drained soils with abundant organic matter and consistent moisture. Light shade is preferred for the best growth. The sori appear along the margins of the pinnule, hence the name marginal wood fern.

Ostrich Fern

Matteuccia struthiopteris
Hardy in zones 2 to 8     
Height 3 to 4 feet (90 to 120 cm)                              
Native to North America, Including Iowa

Ostrich Fern Matteuccia struthiopteris
Ostrich Fern (
Matteuccia struthiopteris)

The foliage of ostrich fern is dark green and arises from a central crown and underground runners. It is adaptable to many sites but prefers locations with abundant organic matter and moisture. Brown, tightly rolled, fertile fronds emerge in late summer and become almost woody.  Plants spread readily, sometimes sending up sprouts from runners 3 feet from the parent plant.  Because of its height and spreading ability, it is best used as a background plant in large areas. Fiddleheads are edible and harvested when 2 to 3 inches high. 

Sensitive Fern

Onoclea sensibilis
Hardy in zones 2 to 9     
Height 18 to 30 inches (45 to 75 cm)                       
Native to North America, including Iowa

Sensitive Fern Onoclea sensibilis
Sensitive Fern (
Onoclea sensibilis)

Sensitive ferns thrive in shaded, moist areas that are slightly acidic. The broad, light green fronds are pinnately compound and are quite attractive. This Iowa native spreads readily by creeping rhizomes and may choke out more delicate ferns. Brown fertile fronds with bead-like segments emerge in late summer.  Plants are sensitive to drought and frost and readily turn brown in those conditions. 

Cinnamon Fern

Osmunda cinnamomea
Hardy in zones 2 to 9     
Height 2 to 5 feet (60 to 150 cm)                              
Native to North America, including Iowa

One of the most distinguishing things about this North American native fern is the cinnamon-colored fertile fronds which have no leafy tissue.  The fertile fronds emerge in spring and die down in summer.  The beautiful green finely divided sterile fronds unfurl in spring and persist all season.  Plants grow best in shaded acid soils that are consistently moist.

Interrupted Fern

Osmunda claytonia
Hardy in zones 2 to 8     
Height 2 to 4 feet (60 to 120 cm)                              
Native to North America

The interrupted fern is one of the earliest ferns to emerge in the spring. The foliage emerges yellow-green in color and changes to bright green as it matures. It thrives in a variety of locations. For the largest growth, locate plants in shaded acid soils that are consistently moist. It does not spread aggressively. Fronds have several pairs of spore-covered pinnae in the middle of the frond, giving it an interrupted look.

Royal Fern

Osmunda regalis
Hardy in zones 3 to 9     
Height 2 to 5 feet (60 to 150 cm)                              
Native to North America, including Iowa

The reddish-brown fiddleheads of royal fern appear in early spring and often go unnoticed until the frond unfurls.  The top ¼ of the frond will have spore-covered pinnae giving the plant a distinctive look.  Because its foliage resembles a locust tree, the plant is sometimes known as locust fern. It is quick to establish in the garden but slow to spread. Royal fern is native to Iowa and many parts of the eastern United States. Best growth occurs in open shade in acidic soils.

Hart’s Tongue Fern

Phyllitis scolopendrium
Hardy in zones 4 to 8     
Height 12 to 18 inches (30 to 45 cm)
Native to Europe

Evergreen fronds are green, leathery, and undivided, giving the frond a strap or tongue shape.  This distinctive frond makes it one of the most recognizable ferns potentially grown in Iowa.  The sori are arranged in rows or stripes up the back of the frond.  Plants grow best in consistently moist but well-drained soils.  They are especially happy on organic limestone-based or more calcareous-based soil.  When not in ideal conditions, they can be quick to die back. When in the right location, plants are easy to grow.  American Hart’s Tongue Fern (Phyllitis scolopendrium var. americanum) grows in eastern North America but is typically more difficult to establish in the garden.

Rock Polypody

Polypodium virginianum
Hardy in zones 3 to 7     
Height 6 to 10 inches (15 to 30 cm)                         
Native to North America, including Iowa

Rock polypody is a low, mound-forming plant with arching evergreen fronds. Fronds are lance-shaped with blunt-tipped lobes. It spreads by thick rhizomes covered with cinnamon-colored scales. It is somewhat difficult to establish in the garden as it is more epiphytic and prefers growing on rocks, boulders, and branches. A related species, Polypodium vulgare, is native to almost the entire state of Iowa and thrives where moist woodland areas exist.

Christmas Fern

Christmas Fern Polystichum acrostichoides
Christmas Fern (
Polystichum acrostichoides)

Polystichum acrostichoides
Hardy in zones 3 to 8     
Height 1 to 2 feet (30 to 60 cm)                
Native to North America, including Iowa

Christmas fern is early to emerge in the spring with evergreen fronds eventually becoming a leathery dark green. The common name comes from its use as decoration by early American settlers during Christmas, not from the boot or stocking-shaped pinnae. It grows optimally in shaded areas with moist, well-drained soils. It can tolerate more sun when ample moisture is available.

Japanese Tassel Fern

Polystichum polyblepharum
Hardy in zones 5 to 8     
Height 1 to 2 feet (30 to 60 cm)
Native to Asia

Japanese Tassel Fern's delicate, finely-divided fronds are glossy green and evergreen to semi-evergreen with dark scaly rachis and stipe.  Plants are not aggressive spreaders.  Grow in well-drained soils with abundant organic matter and consistent moisture.

Additional Ferns for Iowa

Other ferns to try in your garden include:

  • Scott’s Spleenwort (Asplenium ×ebenoides)+
  • Ebony Spleenwort (Asplenium platyneuron)*
  • Silvery Spleenwort (Deparia acrostichoides)*
  • Walking Fern (Asplenium rhizophyllum)*
  • Spinulose Wood Fern (Dryopteris carthusiana)*
  • Shield Fern (Polystichum braunii)+

(+Native to North America;   *Native to North America, including Iowa)

Common Name(s): 
Authors: 

Cynthia Haynes Professor

Dr. Haynes is a Professor of Horticulture at Iowa State University in Ames.  Her primary responsibilities are in teaching and extension.  She teaches several courses for the Department of Horticulture including Home Horticulture and Herbaceous Ornamentals.  She also has extension r...

Aaron Steil Consumer Horticulture Extension Specialist

Aaron Steil is the consumer horticulture extension specialist at Iowa State University where he works with county Extension offices across the state to answer home gardening questions for all Iowans.  This includes information related to trees, shrubs, vegetables, fruits, herbs, perennials, ...

Last Reviewed: 
June, 2023