Most perennial ferns are understory plants and cannot tolerate very high light levels. As with tropical ferns, the same plant will have lush, dark green foliage at lower light levels and tough, light green to yellow foliage at higher light levels. Perennial ferns are not only sensitive to light levels, but also to durations. For example, Cinnamon Fern (Osmunda cinnamomea) is photoperiodic and will enter dormancy caused by short days.
Temperatures will also influence the growth of ferns. When soil temperatures are too low, plants will go dormant, ceasing growth; some varieties will defoliate at this time. Dormancy can improve vigor and color in certain species, such as the Japanese Painted Fern (Athyrium niponicum ‘Pictum’). While low temperatures induce dormancy, high temperatures can also stop growth, especially in species native to cooler climates. Most Polystichum species (Christmas, Korean Rock, Tassel, and Western Sword) and a few Dryopteris (Recurved Broad Buckler) enter “dormancy” during periods of soil temperatures that exceed 95 degrees.
Perennial ferns are light feeders preferring well-balanced formulas (5-5-5) or a 2-1-2 ratio such as (20-10-20) will work; Kelp meal is also a great amendment for ferns. Most grow best at pH levels ranging from 5.5 to 6.5; however, ferns naturally occurring in limestone soils prefer a neutral pH level. These lime-lovers include Southern Maidenhair (Adiantum capillus-veneris) and Japanese Holly Fern (Cyrtomium falcatum). Most prefer rich, well-drained soil; however, vermiculite tends to cause negative effects on fern growth, so this should be avoided. They will not tolerate dry soil; they prefer to be kept evenly moist, though a delicate balance must be maintained—ferns should not be over-watered either. During periods of slow growth, too much water will increase disease and pest susceptibility.
Ferns With Unusual Textures
- Japanese painted
- Beaded wood (Dryopteris bissetiana)
- Crested lady/male (Dryopteris cristata)
- Japanese Holly (Crytomium falcatum)
- Ostrich (Matteuccia struthiopteris)
- Royal fern (Osmunda)
- Soft shield (Polystichum setiferum)
- Sprengeri
- Selaginella
Ferns With Unusual Colors
- Autumn (Dryopteris erythrosora)
- East Indian Holly (Arachniodes simplicior)
- Ghost fern
- Japanese painted
- Lady in Red (Athyrium niponicum)
Ferns for Rock Gardens
- Spleenwort (Asplenium)
- Lip fern (Cheilanthes)
- Polypody (Polypodium)
- Male fern (Dryopteris affinis)
Ferns for Bog Gardens
- Lady fern (Athyrium filix-femina)
- Crested wood fern (Dryopteris cristata)
- Ostrich fern (Matteuccia)
- Cinnamon/Royal fern (Osmunda)
- Chain fern (Woodwardia)
Hardy Ferns Also Used as House Plants
- East Indian Holly
- Japanese Holly
- Korean rock
- Rosy maidenhair
- Southern maidenhair
- Selaginella
- Tassel
More Ferns to Know About
- Adiantum (Maidenhair fern): (NW native is A. pedatum) likes moist, rich, well-drained soil with light shade or filtered sun (prefers limestone/alkaline-pH neutral); spreading habit
- Arachniodes (Bristle fern): closely related to Dryopteris genus; clumping habit and slowly spreading; part shade; mostly evergreen
- Athyrium (Lady fern): (Japanese painted is A. niponicum var. pictum) likes light shade (can sunburn), moist soil; spreading habit
- Blechnum (Deer fern): (native is B. spicant) grows well in shade-part shade and is sun tolerant if given adequate water; clumping habit; evergreen
- Cheilanthes (Lip fern): one of the few drought tolerant ferns; needs good drainage; creeping habit; mostly deciduous
- Crytomium (Holly fern): bold texture and grow best in partial shade; C. fortune is more cold tolerant than Japanese Holly fern; clumping habit; semi evergreen
- Dryopteris (Wood fern, shield fern, male fern, buckler fern): a large and complex genus including popular Autumn fern and Male fern; prefers cool, moist soil with shade or partial sun; can be sun tolerant if given adequate water
- Osmunda (Cinnamon Fern, Royal fern): grows in part sun/shade in wet to moist areas
- Polypodium (Scoulers Polypod fern): low-spreading habit and can be used as a groundcover; prefers shade-part sun; can be semi-epiphytic; evergreen
- Polystichum (NW native is P. munitum Sword fern; Korean rock fern, tassel fern, Alaskan fern are all examples of this large family of North American, hardy, temperate, Asian, and European genus): mostly prefer moist, rich, well-drained soil, but are tolerant of dry periods; clumping habit; glossy foliage; mostly evergreen
- Woodwardia (Chain fern): best in cool, moist, coastal conditions; the NW native Giant Chain fern (W. fimbriata) can grow to 3-5 feet tall/wide; clumping habit; mostly evergreen
- Selaginella: not true ferns, but actually club moss or spike moss; they also produce spores to reproduce and appreciate similar growing conditions; many are garden hardy (best with protection) and others make excellent houseplants
Other Non-Fern Shade-Lovers
- Heuchera/Heucherella (mostly evergreen)
- Helleborus (evergreen)
- Epimedium/Bishop’s Hat (many evergreen species)
- Dicentra/Bleeding Heart (Dicentra spectabilis recently reclassified as Lamprocapnos spectabilis)
- Tricyrtis/Toad Lily
- Begonia grandis/Hardy begonia
- Hosta
- Hakonechloa/Japanese forest grass
- Asarum/Ginger (evergreen)
- Beesia (evergreen)
- Cyclamen
- Sarcococca/Sweet Box (evergreen)
- Daphne
- Fatsia
- Camellia
- Mahonia
- Hydrangea
For amazing photos, ideas, and inspiration go to www.greatplantpicks.org. Also, check out The Plant Lover’s Guide to Ferns, a book by Richie Steffen and Sue Olsen (Timber Press, 2015).