Plants of Muir Woods: Trees, Ferns, and the Forest Floor
Muir Woods is a coast redwood (Sequoia sempervirens) forest, but the redwoods are only one layer of what grows here. The National Park Service describes the monument as an old-growth ecosystem with three distinct layers: the forest floor and its herbaceous plants, a mid-story of broadleaf trees and shrubs, and the high canopy. Each layer supports the others, and together they create the cool, damp conditions these trees need to survive.
The Layers of an Old-Growth Redwood Forest
The Canopy: Redwoods and Their Companions
The dominant tree is the coast redwood. The tallest trees in Muir Woods reach roughly 250 feet, and the oldest are estimated to be at least 1,200 years old. Redwoods do not grow alone up there. The NPS lists several canopy companions that share the upper story:
Douglas-fir
Pseudotsuga menziesii
Scattered among the redwoods, reaches similar heights, holds on to its bark-covered cones.
Western hemlock
Tsuga heterophylla
Fine, soft needles and small, dangling cones; thrives in the wet shade under the redwoods.
Tanoak
Notholithocarpus densiflorus
Leathery evergreen leaves and acorns; a connector species between conifer canopy and broadleaf mid-story.
Pacific madrone
Arbutus menziesii
Smooth red peeling bark, white urn-shaped flowers, orange berries in fall.
Redwoods protect the monument in more than one way: they were the reason the land was preserved in 1908 as a National Monument, and their canopy traps fog, which drips down and waters everything below.
The Mid-Story: Broadleaf Trees
Red alder
Alnus rubra
Common along Redwood Creek, where its roots help stabilize the streambank.
California big leaf maple
Acer macrophyllum
One of the first trees to turn gold in the fall, with leaves up to a foot wide.
The Understory: Shrubs
California rhododendron
Rhododendron macrophyllum
Pink blooms in May and June.
Evergreen huckleberry
Vaccinium ovatum
Small dark berries in late summer; an important food source for wildlife.
Thimbleberry
Rubus parviflorus
Soft red berries and maple-shaped leaves along creek edges.
Salmonberry
Rubus spectabilis
Pink flowers in early spring, orange-to-red berries by early summer.
Ferns: Thirteen Species, Six Families
Ferns are one of the signatures of Muir Woods. According to the National Park Service, the monument is home to 13 species of ferns from six different fern families.
Western sword fern
Polystichum munitum
Evergreen, 2 to 6 feet tall. The large ferns you see in waves along the trail.
Lady fern
Athyrium filix-femina
Deciduous, about 3 feet tall, delicate and lacy.
Maidenhair fern
Adiantum
Small and fine-leaved, often found near seeps and streambanks.
Gold back fern
Pentagramma triangularis
Small, with a yellow powder on the underside of its fronds.
Giant horsetail
Equisetum telmateia
A fern ally with a lineage 300 million years old. Forms bright green colonies along the creek.
The Forest Floor
- Redwood sorrel (Oxalis oregana): clover-shaped leaves that fold up in direct sun and open in low light.
- Mosses and liverworts drape fallen logs and lower trunks.
- Fungi break down the thick duff layer, essential recyclers in an old-growth system.
- Ferns grow in dense colonies, especially near the creek.
Wildflowers
Muir Woods is not a wildflower destination in the traditional sense. The canopy is too dense. But in spring, the shaded floor produces subtle blooms: Trillium (three white petals that turn pink with age), western starflower, fringecup, fairy bells, and Solomon’s seal.
Why the Plant Community Matters
This layered system is not just pretty. It is functional. The canopy captures fog and slows rainfall. The mid-story holds moisture. Ferns and forest-floor plants trap duff and feed soil fungi. Fallen redwoods become “nurse logs” for new seedlings. Remove any layer and the whole system struggles. That is why rope barriers line the boardwalk: stepping off the trail compacts the soil and damages the fragile root and fungal networks that keep Muir Woods alive.
Frequently Asked Questions
How old are the oldest redwoods in Muir Woods?
The oldest are estimated to be at least 1,200 years old, and possibly older. Age is measured without coring the trees, which protects them.
Are there giant sequoias in Muir Woods?
No. Muir Woods contains coast redwoods (Sequoia sempervirens), a different species from the giant sequoias (Sequoiadendron giganteum) of the Sierra Nevada.
When do the rhododendrons bloom?
Typically May into June, in the shaded understory.
Can I pick plants or berries?
No. Muir Woods is a National Monument. Removing any plant material, including berries, leaves, or cones, is prohibited.