Category Archives: Flora

Slough Sedge (Carex obnupta)

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Slough sedge (royalty free from Unsplash)

Sedge grows well along the Pacific Coast. Slough sedge can be found along the coast from British Columbia south to northern California.

This evergreen sedge is not a grass, but can take the place of a grass in wet and shallow bogs, marshes, and riverbanks. It also does well in meadows, ditches, swamps, and muddy areas.

There is only one sedge in our area. The sedge will grow in salty, marshy, and freshwater areas.

Carex obnupta is often found growing near Skunk cabbage (watch for the large yellow flowers).

Slough sedge is available commercially and easily propagated.

Importance

Why this lowly plant is important? It is key to maintaining wetlands functioning. The perennial sedge performs several functions such as:

  • Helping to control and maintain stream banks by minimizing erosion and improving stream structure.
  • Slowing sediment flow allows the nutrients to settle. This generates a nutrient rich habitat and improves water quality.
  • Abating storm water.
  • Supporting wetland species.

Rhizomes

C. obnupta accomplishes these tasks in several ways.

The horizontal, creeping rhizomes (root-like structures) help anchor the plant. The rhizome shoots can also generate new plants creating new Sedge tufts (or clumps) about a foot wide.

A dense, underwater rhizome network develops as the clumps grow into larger beds or colonies.  

Concealing Vegetation

The uneven tufted surface provides concealment, nesting, and bedding for many birds and mammals.  

The tall (up to four feet) male spikes rise above the shorter female flowers. Additional vegetative stems help conceal nest and bedding areas.

Slough sedge (Royalty free Unsplash)

Reproduction

Male flowers spikes typically rise above the female flowers and have yellow pollen at peak bloom time. Female flowers have a white sticky substance for collecting the pollen. Dark, lens-shaped seeds are stratified over the winter.

The fertile and non-fertile stems have different shapes. A cross-section cut of the fertile stems will reveal a triangular shape. Non-fertile, or vegetative stems without flowers have a “W” shape and were harvested for basketmaking.

The process of harvesting helps to move nutrients in that the process of creating more leaves transports nutrients from the rhizomes.  

Wildlife Supported

Birds: Several birds take advantage of the foliage for bedding, nesting, and consume sedge seeds. Birds include game and other marsh/shore/song birds).

Wetland mammals: Muskrats, minks, beavers, and otters use the foliage to conceal their travel.

Insects: Several butterflies and moths are supported including:

  • Umber Skipper (Poanes melane),
  • Common Ringlet (Coenonympha tullia),
  • American Ear Moth (Amphipoea americana),
  • Dun Skipper (Euphyes vestris),
  • Olive Green Cutworm Moth (Dargida procinctus),
  • Elachista cucullate, and
  • Lesser Wainscot (Mythimna oxygala).

NOTE: Slough sedge is considered invasive in some areas and is very difficult to remove.

REFERENCES:
–East Multnomah Soil & Water Conservation District (https://emswcd.org/slough-sedge/)
–USDA, Natural Resources Conservation Service, Slough sedge brochure (www.plants.usda.gov/plantguide/pdf/cs_caob3.pdf) 
–Wikipedia (https://en.wikipedia.org/wiki/Carex_obnupta)
–Univ. of Washington, Bothell (https://www.uwb.edu/wetlands/plants/carex-obnupta)
–California Native Plant Society (https://calscape.org/Carex-obnupta-())

Pacific Aster (Symphyotrichum chilense)

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What’s that pretty little herb with yellow and violet disk flowers?

Pacific Asters (or common California aster) are a native perennial found along the Pacific coast. It inhabits coastal mountains, salt marshes, coastal dunes and bluffs, coastal scrub, and open or disturbed areas.

Courtesy NRCS, Annie Young-Mathews, 2010

This particular aster is very versatile and can be used in bird, butterfly, and bee gardens!

There are nearly 50 different kinds of native asters here in the Pacific Northwest. Asters are part of a very large and diverse plant family call Asteraceae. Despite its Latin name (chilense), it does not occur in Chile.

Fall Food Source

Pacific Aster grows 1- to 3-feet tall and hold cheery disk-shaped blooms on a stalk (inflorescence) in late summer through fall. It provides a late-season food source for all kinds of pollinators including moths, bees, butterflies, and hummingbirds.

This structure attracts many beneficial flying butterflies and insects such as:

  • Northern Checkerspot, Field Crescent and Pearl Crescent butterflies
  • Wavy-lined emerald, Salt-and-pepper-Geometer, Dingy Cutworm, and Olive-shaded bird-dropping moths. 

Flower heads have yellow disk center florets and fringes of many narrow light purple ray florets. Its hairy leaves are narrowly oval-shaped, pointed, and with finely serrated edges.

Propagation and Spread

Pacific Asters spread by rhizomes. The fibrous root system digs deep in to the soil making this plant good at stabilizing slopes and drought tolerant once established. Pacific Asters do not like soggy roots in the winter.

An early spring prune (one-third to one-half) will make the plants more bushy and wind tolerant more wind. Deadheading during the season produces more flowers. At season end, the plants can be cut or mowed to the ground in winter. Likes full sun to partial shade.

Propagate your own from seed: No treatment needed. Seeds may have little fluffy bits attached which help them carry in the wind. This fluff does not need to be detached. Just sprinkle a handful of collected seed fluff in the desired area in the spring and watch for sprouts with a week. Caution when weeding! It will look like a common weed so be aware when pulling.

A wide variety of asters are now available through several nurseries. They are great companion plants that work well with other shrubs and perennials along the coast.

Even better? This aster will tolerate high salinity, there are no known pests or problems, and they are deer resistant!

REFERENCES:
–USDA Natural Resources Conservation Service, Plant Fact Sheet for Pacific Asters (http://plants.usda.gov)
–HGTV (https://www.hgtv.com/outdoors/flowers-and-plants/aster-flowers)
–Wikipedia, symphyotrichum chilense (https://en.wikipedia.org/wiki/Symphyotrichum_chilense)
–Watershed Nursery, plant finder (https://www.watershednursery.com/nursery/plant-finder/symphyotrichum-chilensis/)
–Portland Nursery (https://www.portlandnursery.com/perennials/aster/)

Bracken Fern (Pteridium aquilinum)

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Just like in classic murder mysteries… a pretty face pressed behind glass and poising as art is really a deceptive killer.

Bracken fern (royalty free from Unsplash)

Perhaps being a deceptive killer is really just a clever survival strategy. Fossil records over 55 million years old show Bracken ferns is one of the oldest plants around.  

Bracken ferns grows throughout all temperate and tropical regions. In Oregon we see the subspecies P. aquilinum pubescens or Western Bracken which grows from Alaska to Mexico and east to Wyoming, Colorado, and Texas.

The plant prefers well-drained soils and will often grow on hillsides. It will also grow in burned-over areas near woodlands or other shady places and in open pastures and ranges with sandy, gravelly soils.

Colonization

It colonizes areas two different ways. Triangular fronds may reach 16 feet or taller in a season. Fronds provide some shade and protection but discourage native species through large volumes of plant litter and chemical emissions.

Tiny, lightweight spores are on the underside of the frond. Spores easily spread in the wind or fall from fronds to the ground.  

Spores sprout into plants and lead to the development of deep-set, black roots called rhizomes. Bracken rhizomes creep underground up to 1,300 feet sending up fronds as they grow. The lowly Bracken is surprisingly one of the largest plants in the world.

Dried Bracken fern (royalty free Unsplash)

Silent Killer

Every part of the Bracken contains poisonous, carcinogenic compounds—even the spores are toxic. The plant emits poison into the surrounding soil through spores and leaf litter. These toxic chemicals remain in the soil even after the fern is removed.

Bracken fern is toxic to dogs, cattle, sheep, horses, and pigs. This fern is linked to cancer in humans. Even milk from cows grazing Bracken fern may be hazardous to humans.

Grazing animals may consume Bracken when normal foods are unavailable (such as during adverse weather). Ptaquiloside has a cumulative effect. Cattle consuming large amounts of Bracken in short periods of time can become poisoned. The disease has a delayed onset and poisoned animals rarely recover. The disease is often chronic in horses.

Some cultures consume young fronds called fiddleheads and rhizomes. Ptaquiloside will damage DNA and potentially lead to digestive tract cancers. There are ways to reduce the level of this chemical through cooking and other detoxifying techniques.

Hydrogen cyanide is released when mammals or insects eat this fern. This chemical causes repeated insect molting leading to death. Bracken is under investigation as a possible new insecticide.

Eradication

Bracken invasions threaten biodiversity and habitat loss. Once established, this deciduous plant and its chemical foot print are very difficult to eradicate.

Removal and long-term management can encourage the re-establishment of native habitats. Bracken ferns are listed as an invasive species in several areas and considered to be among the world’s worst weeds.

REFERENCES:
–Encyclopedia Britannica (https://www.britannica.com/plant/bracken)
–USDA Agricultural Research Service (https://www.ars.usda.gov/pacific-west-area/logan-ut/poisonous-plant-research/docs/western-bracken-fern-pteridium-aquilinum/)
–Wikipedia, Bracken (https://en.wikipedia.org/wiki/Bracken)