Category Archives: Flora

Western Sword Fern (Polystichum munitum)

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Western Sword Ferns grow almost everywhere along the Pacific Coast. Indeed, they can be found from southeastern Alaska to southern California, across the U.S., and in several countries.

Western Sword Fern (royalty free Unsplash, by Danieli Cordiero)

These plants are easy to identify and have been around for a very long time. Fossil records of fern-like plants date back almost 400 million years ago. Ferns, and similar plants, were a dominant plant species until about 230 million years ago.

Identification

They are easy to identify. The dark green fronds are shaped somewhat like a sword (long and narrow) or dagger (when young). Fronds will grow up to nearly six feet long in the right environment with ample moisture.  

The fronds grow in a clump around a rhizome (a root structure) typically in soil that is acidic, well-drained, and rich in humus. Fronds will live for up to two and a half years and remain attached to the rhizome even after withering.

Fronds

Each frond includes up to 100 small, dark green leaves. On the back side of the leaf, there are rows of small balls. These small balls contain 32 to 64 spores that are part of the reproduction system.

Spores are often distributed on the wind or disturbance that sets the spore floating. A spore contains only half of the chromosomes needed to create a new fern.

Once the spores touch ground, they develop both male and female sex organs, and sperm and eggs. The sperm fertilizes the egg, completing the needed chromosomes, and a new fern develops.  

Medical

The spores have some interesting traditional medical uses. The Cowichan tribe used the sword fern to counteract a stinging nettle rash. Simply rub the spore side of the leaf against the infected area to take the pain away.

The leaves have been used to cure sore throats (the Swinomish tribe of Washington state), and chewed during childbirth (Lummi tribe of Washington).

Food

Several other Native American/First Nations people would roast, peel, and eat the rhizomes in time of food shortages.

Predators

Deer and rabbits will eat sword ferns, along with other rodents. The Washington Dept. of Wildlife has a handy table that provides a list of plants that are eaten by Mule, and Black- and White-tailed deer (https://wdfw.wa.gov/sites/default/files/2019-03/living-with-deer-tables-1-2_0.pdf).

The new, succulent growth is easily damaged and difficult to detect. Deer damage can be more ragged looking. Rodent and rabbit damage appears to be more clipped. Elk and human damage may show up as crushed fronds or rhizomes.

Knowing what kind of animal is doing the damage will make it easier to develop deterrents. Not all critters will eat the plant but can crush it when walking through a clump or tear at the rhizome when trying to remove a leaf.

Growing it

Western Sword Ferns are easy to transplant and grow in your garden. They can provide wonderful texture, stabilize soil, protect soil moisture, and even grow in full sun with enough water.

They can be transplanted/divided in the early winter and spring very easily. The location and exposure will dictate techniques to use. In general:

  • Add compost to the hole to give the plant a good start.
  • Transplanting during hot and dry weather is not recommended, however it is possible if the fronds are dry and the plant has access to moisture. More shade, less protection needed.
  • Make sure that the rhizomes peak out or are close to the soil surface or are just lightly covered (with compost) for sun protection.
  • Keep the soil moist for the next year to develop the roots and help make the plant fairly drought resistant.   
  • Finally, if you purchase a Western Sword Fern make sure that it is a “Polystichum munitum” and not an imposter. Some imposters can become or are invasive plants.  

REFERENCES:
–Washington Dept. of Fish and Wildlife, Sword Ferns (as noted above).
–Wikipedium, western sword fern (https://en.wikipedia.org/wiki/Polystichum_munitum)
–US Dept of Agriculture,  Conservation Plant Data (https://plants.usda.gov/growth_habits_def.html)
–SF Gate, Interesting Facts About the Western Sword Fern (https://homeguides.sfgate.com/interesting-western-sword-fern-70704.html)
— Sword Fern Plant Care: How To Grow Sword Ferns (https://www.gardeningknowhow.com/ornamental/foliage/sword-fern/sword-fern-care.htm)

Vine Maple (Acer circinatum)

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Let’s go a little wild…

Vine Maple is most likely growing wild in your neighborhood. This small native tree can be found from Alaska south to northern California and from the Cascade Mountains to the Pacific Ocean.

Vine Maple (courtesy of OSU Extension)

Why you want one (or more)

This interesting tree (not a vine) fits into almost any garden—even small gardens and provides nearly year-around interest. Interesting features include seasonal leaf colors, flowers, bark, seeds, and wildlife support.

Vine Maple (Acer circinatum) is a close relative of the Japanese Maple (Acer palmatum – like a palm). Circinatum refers to the rounded or circular leaf shape, typical of Vine Maples.

There are approximately 150 maple species worldwide, most originating from eastern Asia. Three native maple species grow in the Pacific Northwest (Big-Leaf, Douglas, and Vine).

Excellent Companion Plants

Once established Vine Maples are almost pest free and make an excellent companion plant, particularly once they are established. It is a favorite for many gardeners. Why? Because they…

  • Are hardy to USDA zones 5-9. They will appreciate some protection from strong winds.
  • Grow well in a variety of soil types, particularly the common slightly acidic soils found in the Northwest. Give them a yearly dressing of compost and they are happy!
  • Tolerate varying moisture levels, including moist to wet areas, and can be used for erosion control.
  • Tolerate a variety of light/sun levels. They can function as a soft understory plant or even a showy fall specimen based on the light level. Full sun will bring on brilliant fall leaf shades of red and orange; shade produces deep golden leaf colors in the fall. Note to self: More sun requires more regular water until established.
  • Can be pruned to maintain health or height, bring branches off the ground (so they don’t root new plants), or to enhance shape. The height can get to 15-20 feet. Want something smaller? Choose one of the new dwarf cultivars that are significantly more bush-like.
  • Are easier to care for in a garden compared to Big-Leaf and Douglas maples. Both of these maples are significantly larger.
    • Big-Leaf maple leaves are very large and can create problems in a smaller garden, not just in more raking and clean-up, but much more. Plants and soil under the trees can be smothered (to death), air and moisture movement reduced, and make soil more acid over time.
    • The Douglas maple is nearly twice as large compared to the Vine maple. These maples tolerate drier and colder environments and can be found here and eastward beyond the Rocky Mountains.  
Vine Maple in early fall (courtesy OSU Extension)

Seeds, Flowers, and Leaves

All maples have certain common aspects.  For instance, the paired seeds, create a wing that will twirl in the air. Seed size will vary depending on type of maple.

These seeds are produced by tiny white flowers with wine-colored sepals. Flowers attract butterflies and bees; seeds attract birds, squirrels, and rodents.

Vine Maple flowers (courtesy OSU Extension)

Leaves are deciduous and drop in the fall. Leaves balance on the stem positioned opposite to each other. Vine maple leaves are all nearly the same length when mature with 7-9 regularly spaced lobes. Young stems are typically pale green. Summer foliage is preferred by deer and elk.

Native American Uses

Stems and branches were used to create beautiful baskets and fish traps. This relatively fast-growing tree was also used for firewood.

To learn more or access seed check out the Maple Society at https://maplesociety.org/en-gb.

REFERENCES:
—Acer circinatum (https://plants.ces.ncsu.edu/plants/acer-circinatum/)
–Pacific Northwest Natives (http://www.pnwplants.wsu.edu/PlantDisplay.aspx?PlantID=36)
–Oregon State University, Acer circinatum (https://extension.oregonstate.edu/node/146966/printable/print)
–Wikipedia, Acer circinatum (https://en.wikipedia.org/wiki/Acer_circinatum)
–Portland Nursery, Acer circinatum (https://www.portlandnursery.com/natives/acer-circinatum/)

Black Cottonwood (Populus trichocarpa)

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What does it take to earn a regional and national title? The Black Cottonwood of Willamette Mission State Park could tell you.

Black Cottonwood’s are native to Oregon and can be found from Alaska through northern California, and eastward into Montana. Cottonwoods are typically very tall and large trees and are the largest popular species in the Americas.

Image courtesy Oregon State University Extension

Typically, they will grow up to 164 feet and have a trunk diameter over 6.6 feet. Our winner, the “Willamette Mission Cottonwood,” measures 155 feet (47.26 m) tall, 29 feet around (8.8 m), with a crown that stretches just over 93 feet.

Cottonwoods live relatively short-lived trees. Some will reach 400 years old.

As they age, the bark hardens becoming thick and fissured. By age 20, cottonwood bark has thickened enough to help protect the tree from fire. At this point, the bark is hard enough to cause sparks when cut by a chainsaw.

Seedlings and saplings can be killed or damaged by fire. Repeated fire can completely eliminate all Black Cottonwood from an area.

This tree is a natural colonizer and after a burn may be able to colonize large areas with good light, moist soil, and bare mineral soil from seed.

What makes this an important tree?

The light-colored hardwood has a fine, even texture with indistinct growth rings and a fine grain. The wood is light weight and ideal for making a number of products (such as pallets, boxes, crates, furniture, high-grade paper, fuel pellets, and plywood). 

Cottonwoods are frequently used for windbreaks, shelterbelts, and road screening. The aggressive root system makes it an effective soil stabilizer and useful in riparian and aquatic restoration projects.

Research is continuing on species hybrids as potential sources of biomass. They grow faster than any other northern temperate region tree and are easily propagated.

They are fast to re-sprout, and quick to harvest. Some sites have so much existing seed, they don’t need to be seeded after harvest.

(This raises the question of ‘Could these hybrids become a future noxious and invasive weed?’)

Even the critters like it

Black cottonwood provides cover and food for deer, elk, beaver, and birds. Even rotten trunks are useful in areas with scarce shelter.  

Black Cottonwood male flowers (image courtesy Oregon State University Extension)

But…

Many people are, unfortunately, negatively impacted by the copious amounts of tree pollen. Male trees release pollen in late May and June, about three weeks before the females release seed.

Trees create an abundance of seeds every year. Seed release resembles a serious snow storm.

Cotton-like hair is attached to each seed. This hair keeps seed afloat on air or water for long distances. The seed can sprout one day after touching the ground!

Seeds and cotton-like hair (image courtesy OSU Extension)

Native Americans discovered that the tree resin was good for treating sore throats, coughs, lung pain, and rheumatism, and that the inner bark good for creating soap.

And then…

Perhaps the most perplexing questions about this large tree is how one would go about measuring a giant one. I guess you just have to climb to the top, drop a very long tape measure, and hold on tight…  

REFERENCES
–Heritage Trees, Oregon (https://oregontic.com/oregon-heritage-trees/willamette-mission-cottonwood/)
–Oregon State University, Landscape Plants, Populus trichocarpa (https://landscapeplants.oregonstate.edu/plants/populus-trichocarpa)
–USDA, Natural Resources Conservation Service, Plant Guide, Black cottonwood (Populus balsamifera L. ssp. trichocarpa (Torr. & Gray ex Hook.) Brayshaw (https://plants.usda.gov/core/profile?symbol=POBAT)
–King5 “Is cottonwood fluff causing your allergies? (https://www.king5.com/article/news/local/take-5/take-5-is-cottonwood-fluff-causing-your-allergies/281-557522159)
–Monumental Trees, Exactly Measuring Tree Height (https://www.monumentaltrees.com/en/content/measuringheight/)