September 1, 2018
If redwoods, firs and bays are the stars of our Marin forests, then ferns are important members of the supporting cast. The ferns along our shady coastal trails invite us into a deeper appreciation of our verdant woodland environment. It’s impossible to imagine the towering redwoods of Muir Woods without the lush green carpet of ferns underneath.
Ferns are among the oldest living plants on Earth and it is estimated that there are currently around 10,500 species broadly ranging in size and diversity. At least 50 species are native to Marin. Because ferns have no showy flowers and produce no fruit or seeds, they are often overlooked when choosing garden plants. Ferns are also perceived as delicate, needing special care and requiring extra water. However, many of our native ferns are hardy survivors and can bring that woodsy vibe into your garden with little effort.
Ferns, unique within the plant kingdom due to their reproduction by spores, are known for the beauty of their leaves (fronds). Fronds of different native fern families vary in size, shape,and color. New fronds grow from the base of the fern, uncoiling in fiddleheads (croziers). When considering which native ferns might complement your garden, keep in mind that they prefer partial or full shade, good drainage and rich soil. However, most have adapted to withstand competition from native trees, which is why they flourish under redwoods. All are considered deer resistant and some are deciduous, so they will turn brown and go dormant in late summer or winter.
Small but resilient
The smaller native ferns (under 2 feet in height), for example maidenhair and polypody, are beautiful as ground covers or in rock gardens. Despite their delicate appearance, maidenhair ferns such as the Southern maiden hair (Adiantum capillus-veneris) and the five-fingered fern (Adiantum aleuticum), can be amazingly resilient with regular water in a well-drained site. The native polypody ferns include the California polypody (Polypodium californicum) and the leather leaf fern (Polypodium scouleri). The polypody ferns tolerate different soil conditions and can grow in oak-shaded areas.
Midsized ferns that reach 2 to 4 feet in height include the coastal wood fern, lady fern and deer fern. All are attractive low-maintenance garden additions. The coastal wood fern, (Dryopteris arguta), is both evergreen and drought tolerant. Lady fern, (Athryrium felix-feminina), with its light lacy green fronds, looks lovely massed around taller plants. Deer fern (Blechnum spicant) is another good choice for a shady woodland garden.
In the larger fern category, the western sword fern (Poliystichum munitum) is a familiar evergreen fern growing throughout our moist shaded forests. It is easy to establish and can reach a height of up to 5 feet. California’s largest native fern is the giant chain fern, (Woodwardia fimbriata). Typically its evergreen arching upright fronds grow to a height of 4 to 6 feet, and can add dramatic interest to your landscape.
In contrast to those previously mentioned, bracken fern (Pteridium aquilinum) is a deciduous native fern that is common along Marin trails but is not a good choice for your garden. It has coarser fronds that spread out rather than clump, making it more invasive than other ferns. It is poisonous to livestock and possibly carcinogenic when consumed by humans.
Not much care
Once established, ferns require little care and can be kept attractive by maintaining the needed soil and moisture conditions and occasionally trimming off dead fronds. Most also grow very well in containers. A word of caution — it is illegal to collect wild plants from public lands so don’t be tempted to bring home a fern on your next hike. All the ferns mentioned in this article are available commercially and it is best to buy a plant that is already conditioned to garden life. The California Native Plant Society website lists nurseries where native ferns can be purchased.
Could your garden use some fronds? Despite their shady reputation, ferns make excellent companions.