Native Plants PNW

WTU Herbarium Image Collection, Plants of Washington, Burke Museum

E-Flora BC, Electronic Atlas of the Flora of British Columbia

USDA Forest Service-Fire Effects Information System

Virginia Tech ID Fact Sheet

Native Plants Network, Propagation Protocol Database

Native American Ethnobotany, University of Michigan, Dearborn

Western Hemlock, Tsuga heterophylla

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Western Hemlock The Pine Family–Pinaceae

Tsuga heterophylla (Raf.) Sarg.

(TSOO-guh het-er-oh-FILL-uh)

Names: The genus name “Tsuga” comes from Japanese words meaning “mother” and “tree.” The species name heterophylla, literally means different leaves. This refers to the different lengths of needles found along a branch. Hemlock trees are sometimes called “Hemlock Spruces” to differentiate them from the herbaceous Poison Hemlock, which is in the Parsley Family.

Relationships: Of the 10 species of this genus, 6 are native to eastern Asia, and 2 to eastern North America. The Mountain Hemlock, Tsuga mertensiana, also occurs in our area mostly in the Mountains.

Distribution of Western Hemlock from USGS ( “Atlas of United States Trees” by Elbert L. Little, Jr. )

Distribution: Western Hemlock occurs from the southern coast of Alaska to the northern coast of California and the Cascade Range of central Oregon. It also occurs in the Rocky Mountains of Canada, Montana and Idaho. Western Hemlock is considered the climax species in most of our area. That means that, in theory, if forests are left alone and allowed to grow undisturbed indefinitely, Western Hemlock would be the dominant species. The Western Hemlock Ecological Zone extends from British Columbia through the Puget Sound Region south to Oregon where it splits along the Coast Ranges and Western Cascades. It is bounded by the Sitka Spruce Zone along the coast in the west and the Subalpine Zone in the Cascade Mountains in the east.

Young Western Hemlock with a drooping leader.

Growth: Western Hemlock typically grows 150-195 feet (45-60m). The tallest Western Hemlock is over 240 feet (73m) tall. The oldest are over 1200 years old.

Habitat: Seedlings of Western Hemlock often begin life on the decaying wood of “nurse logs.” or stumps in the shade of Douglas Firs. They usually start out growing slowly in the shade, much faster in full sunlight when an event occurs that opens it up to the sun. By studying the different sizes of growth rings you can often tell when a tree was growing in shade vs. sun. It grows on fairly dry to wet sites and is very shade tolerant.

Wetland designation: FACU-, Facultative upland, it usually occurs in non-wetlands.

The different sized needles of Western Hemlock.

Diagnostic Characters: Western Hemlock is usually recognized by its drooping top and its different-sized needles in flat sprays. Its small, woody cones are usually less than an inch (2.5cm) long.

In the Landscape: The fine textured, fern-like foliage of Western Hemlock gives it a graceful, delicate appearance. This beautiful tree can be grown singly, in drifts or used as a screen.

Western Hemlock cones

Phenology: Bloom Period: Mid-spring –Mid-April is typical, but may range from March-June (earlier in southern coastal areas, later at high elevations, interior and northern stands). Cones begin to mature in August; seeds are fully ripe by mid to late September but cones do not open until October.

Propagation: For the best results, seeds of Western Hemlock should be stratified at 40ºF (4ºC) for 90 days. Sown seeds should not be covered; they germinate on the surface of the soil. Seed can be stored up to 5 years at 32ºF (0ºC). Propagation by cuttings is difficult but possible with hormone treatment, misting and bottom heat. Western Hemlock has been grown successfully in the laboratory using micropropagation techniques. For small quantities, hemlocks may be propagated by layering.

A bonsai of Western Hemlock at the Pacific Rim Bonsai Collection in Federal Way.

Use by People: Western Hemlock is the second most important timber tree in the northwest. The lumber is sold as “Hem-Fir” and is used for making treated lumber. It is one of the best pulpwoods for making paper products. It is also a principal source of cellulose fiber used for making cellophane and other products. Natives mostly used the wood for firewood. Young trees and saplings were used for poles and fish traps. The bark was used to make a reddish brown dye or paint and as a tanning agent. The pitch of hemlock was used on the face, cosmetically and to prevent chapping.

Use by Wildlife: Hemlocks are favorite nesting trees for many birds. Pine Siskins, Crossbills, Chickadees and Deer Mice eat the seeds. Porcupines and Douglas Squirrels and other mammals also eat the bark. Deer and elk eat the foliage and twigs.

Links:

WTU Herbarium Image Collection, Plants of Washington, Burke Museum

E-Flora BC, Electronic Atlas of the Flora of British Columbia

USDA Forest Service-Fire Effects Information System

Virginia Tech ID Fact Sheet + Landowner Fact Sheet

Native Plants Network, Propagation Protocol Database

Native American Ethnobotany, University of Michigan, Dearborn

National Register of Big Trees

What is a Cedar?

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In my early career as a horticulturist, it often puzzled me why so many different trees that weren’t even closely related bore the common name “Cedar.” I found the answer several years ago while looking through a book about the world’s forests–Trees given the name cedar all share the feature of having aromatic wood. The resins and oils that give the wood its wonderful fragrance make these woods extremely resistant to insects and rot. Because of this property, all “cedars” have had an important role in the history and culture of people throughout the world.

True Cedars have needles.

The true cedars are in the Pine family and are represented by three main species: the Atlas Cedar (Cedrus atlantica) native to Northern Africa; the Deodar Cedar (C. Deodara) native to the Himalayas; and the Cedar of Lebanon (C. libani) native to the Middle East. The Cedar of Lebanon is often referenced in ancient mythologies. King Gilgamesh (~2700 B.C), in an epic story, killed the guardian of the forest and chopped down a great Cedar Tree and then proceeded to plunder the whole forest! Cedar of Lebanon is also mentioned in the bible and was thought to have been used to build King Solomon’s Temple. The Egyptians used the resin and sawdust for mummification. Unfortunately, as in much of the old world, most of the forests were cut down long ago, leaving only a few remaining natural stands. Because of its slow growth, it is of little economic importance today, except as an ornamental tree. All of the true cedars have weeping forms that are very popular in the horticultural trade.

The Australian Red Cedar (Toona ciliata, syn. Cedrela sinensis) is not even a conifer but a deciduous flowering tree in the Mahogany family!

In the Redwood family is the Japanese Cedar (Cryptomeria japonica).

Most of the “Cedars” we are familiar with are in the Cypress family. One of the most well known is the Eastern Red Cedar (Juniperus virginiana). It is a tree juniper and is used in making closets and cedar chests. The Incense Cedar (Calocedrus decurrens) is native to Oregon & California and has been used to make pencils. In the False-cypress genus is the Atlantic White Cedar (Chamaecyparis thyoides), native to the east coast; and the Port Orford Cedar (C. lawsoniana, also known as Lawson Cypress) from Southern Oregon. The most important “cedars” in our area are the Western Red Cedar (Thuja plicata) and the Alaska Yellow Cedar (Callitropsis nootkatensis)!

All the “cedars” are prized as ornamental trees. Although many are too large for a small yard, the different forms, growth habits, color variations, and textures of “cedars” make them a showpiece in any setting.

Climate

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Climate plays a major role in determining what plants can be found naturally or can survive in any location. As children we learn that there are different types of habitats found throughout the world: deserts, grasslands, alpine meadows, tundra and various kinds of forests. I used to wonder why conifers dominate our forests here in the Pacific Northwest. In other areas of similar latitude– the eastern United States, Europe and Asia–deciduous forests predominate. Evergreen coniferous forests are usually found at more northerly latitudes.

Most people believe that it rains in Seattle and the Pacific Northwest year-round, although it does rain much of the year, our great secret is that it is usually dry and sunny (but not too hot!) in July and August. The weather patterns in the Pacific Northwest are influenced by its proximity to the Pacific Ocean. Our maritime climate is characterized by relatively warm, wet winters and relatively cool, dry summers. In the winter, warm, moist air from the southwest flows into the area, as the air cools, the moisture precipitates as rain (or snow if it gets cold enough). In contrast, cool, dry air coming from the northwest, delivers little rain in summer.

Evergreen plants are able to grow whenever there is adequate water and favorable temperatures. If it is too dry they close the small pores, stomates, on their leaves that allow gas exchange, halting photosynthesis. Evergreen leaves are waxy and often small to minimize moisture loss through epidermal surfaces. Dormancy can occur when it is either too cold or too dry.

In some parts of the world, such as Madagascar and Costa Rica, there are summer deciduous forests, where shrubs and trees lose their leaves in the summer! Our deciduous trees and shrubs prefer moister areas near streams and rivers. If summer has been too dry, they too will start turning color early and start shedding leaves before fall has even arrived.

Many of our native evergreens, although adapted to wet winters, do not perform well with summer irrigation; examples include: Pacific Madrone (Arbutus menziesii), Snowbrush, (Ceanothus velutinus), Hairy Manzanita, (Arctostaphylos columbiana), and Oregon Boxwood (Paxistima myrsinites). Pacific Rhododendron (Rhododendron macrophyllum) and Oregon Grape (Mahonia aquifolium) can withstand some irrigation.

Evergreen Huckleberry (Vaccinium ovatum) and Salal (Gaultheria shallon) are the dominate undergrowth shrubs in our second-growth conifer forests. They are both outstanding plants for the landscape that are adapted to our dry summers; with beautiful evergreen leaves prized by the florist industry and berries prized by people and wildlife.

Dry summers can cause severe plant stress. Newly planted landscapes are especially vulnerable. It is a common site to see dead plants in new landscapes that were not irrigated sufficiently. If you plant in July and August, it is important that the new plants are watered adequately but not overwatered! Any plants that were grown in a greenhouse or shadier locations will need to be “hardened off” before planting. This is done by exposing them incrementally to outdoor temperatures and increasing light levels a few weeks before planting. “Sun leaves” need to replace ”shade leaves,” which will be burn in the hot sun.

The end of summer or beginning of fall is a good time to start planning new landscapes, so that you are ready to start planting as soon as there is regular rainfall. Trees and shrubs planted in fall and winter have a better chance of survival because they are able to grow roots into surrounding soil using stored food reserves. But remember, even natives may need supplemental irrigation the first couple of summers!

Western Red Cedar, Thuja plicata

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Western Red Cedar The Cypress Family–Cupressaceae

Thuja plicata Donn ex D. Don

(THOO-yuh ply-KAY-tuh)

My cat Silky at the top of a Western Red Cedar

Names: Western Red Cedar is also known as Giant Arborvitae. Arborvitae literally means “tree of life.” Plicata means plaited or folded like a fan; referring to how the leaves are folded and compressed next to the tree’s branchlets.

Relationships: It is one of only four species in this genus; two are from eastern Asia. The American Arborvitae or Northern White Cedar, Thuja occidentalis is native to the northeastern United States and eastern Canada and has several cultivated varieties, with columnar forms that make good screens and smaller “globe” forms that are good for foundation plantings. Many different types of trees are called “Cedars” see the article on What is a Cedar? for more information.

Distribution of Western Red Cedar from USGS ( “Atlas of United States Trees” by Elbert L. Little, Jr. )

Distribution: Western Red Cedar grows from southeast Alaska to northern California and east to northwestern Montana.

The largest Western Red Cedar is near Lake Quinault in the Olympic Rainforest. Only about a 2 foot wide strip is still alive.

Growth: Western Red Cedars typically grow to 120-150 feet (35-45m); the tallest today are about 200 feet (60m) tall. The widest are about 19 feet (6m) in diameter. These giants are found mostly in the old-growth coastal rainforests of the Olympic Peninsula and Vancouver Island. Some may be 1400 years old or older.

Wetland designation: FAC, Facultative, it is equally likely to occur in wetlands or non-wetlands.

Cedar bark in vertical stripes of red & gray.

Scale-like leaves are tightly compressed against the branchlets.

Diagnostic Characters: Western Red Cedar is easily recognized by its reddish or gray fibrous bark. The scale-like leaves are pressed tightly to stems, having the appearance of flattened braids in lacy sprays. The foliage has a sweet chamomile or tansy odor when crushed. Cinnamon-brown cones are small and elongated and stay attached to branches for a long period of time. Large branches emerge from the main trunk and droop downward, turning up at the ends.

In the landscape: Trees can be planted singly or in groves. They look best when lower branches are allowed to spread, drooping down to the ground and arching back up again. Western Red Cedar prefers moist to wet soils.

Persistent woody cones of Western Red Cedar.

Phenology: Bloom Period: Mid-spring; Mid-April is typical, but may range from March-June (earlier in southern coastal areas; later at high elevations, interior and northern stands). Cones mature in August; seeds are dispersed September through November.

Propagation: Seeds of Western Red Cedar do not require a stratification period, however, a stratification period at 40ºF (4ºC) for 60 days may aid germination in dormant seeds. Seeds may remain viable for 7 years stored dry at 0º F (-18ºC). Germination rates vary from 34-90%. Seeds should not be covered; they germinate on the surface of the soil. Heel cuttings (cuttings where a small piece of older wood is retained at the base) are best taken July-September. Rooting is most successful when cuttings are treated with 2000ppm IBA, stuck in a sand-perlite or peat-perlite media and overwintered in a cold frame. Western Red Cedar may also be propagated by layering, which often occurs naturally in the wild. Seedlings and naturally layered cedars are easily transplanted.

A “Culturally modified” Western Red Cedar on the Makah Indian Reservation

Use by People: Western Red Cedar was the most important tree to native people. For them it really was the “tree of life.” Native people rarely felled cedars; instead they used fallen logs or split off boards from standing trees. The decay resistant wood of these trees was used for building long houses, totem poles, canoes, cradles, and many kinds of tools and other items. Women collected the bark by making a horizontal cut in the bark, prying it up and pulling out away from the tree, leaving a long wedge-shaped scar. Some of these “culturally modified trees” can still be found along hiking trails. The bark was shredded, woven and made into clothing, mats and other items. The limbs of cedar trees were twisted into rope. Baskets were made from the roots.

A bailer & berry picking basket from the Cathlapotle Plankhouse located on the Ridgefield National Wildlife Refuge.

Western Red Cedar is still an important timber tree today although the second-growth wood is not as resistant to decay, as was the old-growth wood. The production of Cedar shakes and shingles was a big business in the last century, but has declined due to limited availability of old-growth wood and building codes designed to reduce the risk of loss due to fire. Western Red Cedar is still frequently used for interior and exterior siding, decks, fencing, other outdoor structures and furniture.

Western Red Cedar stumphouse at Guillemot Cove Nature Preserve in Seabeck.

Use by Wildlife: Western Red Cedar provides cover for several wildlife species. The seeds may be eaten by Pine Siskins. Deer and elk eat the foliage and twigs. Small mammals use cavities in Western Red Cedars for dens; birds use cavities for nests.

An old Cedar growing within the trunk of an older burned out stump with typical swooping branches.

Links:

WTU Herbarium Image Collection

E-Flora BC, Electronic Atlas of the Flora of British Columbia

USDA Forest Service-Fire Effects Information System

Virginia Tech ID Fact Sheet + Landowner Fact Sheet

Native Plants Network, Propagation Protocol Database

Native American Ethnobotany, University of Michigan, Dearborn

National Register of Big Trees

Douglas Fir, Pseudotsuga menziesii

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Douglas Fir The Pine Family–Pinaceae

Pseudotsuga menziesii (Mirb.) Franco

(soo-doe-TSOO-guh men-ZEE-zee-i)

Names: Douglas Fir is named after naturalists, David Douglas and Archibald Menzies. The genus name, Pseudotsuga literally means “false hemlock.” It was once known as P. taxifolia (meaning yew-leaved).

Relationships: It is one of only five species in its genus. Three species from Asia and the other, Big Cone Douglas Fir, Pseudotsuga macrocarpa has a limited distribution in Southern California.

Distribution of Douglas Fir from USGS ( “Atlas of United States Trees” by Elbert L. Little, Jr. )

Distribution: Our Douglas Fir grows from sea level to subalpine mountain sites and has a large distribution from Western Canada down the Pacific coast to central California, and from the Canadian Rockies south to isolated communities in Mexico

Old Growth Douglas Fir in the Olympic Rainforest

Growth: Douglas Fir grows rapidly, especially when young. It typically grows 200 to 240 feet (60-75m) tall. The tallest Douglas firs today are just over 300 feet (90m); historically Doug firs may have attained a height of 400 feet (120m); taller than today’s redwoods! In cultivation, they easily reach 40-80’ (12-24m)

Damage caused by a lightening strike on Douglas Fir.

Habitat: Douglas Firs grow in moist to extremely dry sites. In ecological terms they are considered both early-successional (they are one of the first trees to colonize an area after a disturbance) and late-successional (they often occur in old-growth forests, just because they live so long– up to 1300 years!). Douglas Fir is a primary component of moist forests in the Western Hemlock ecological zone. Infrequent, widespread, stand-replacing fires, (usually caused by lightening strikes) naturally occur at perhaps 400- to 500-year intervals.

Wetland designation: FACU, Facultative upland, it usually occurs in non-wetland but is occasionally found in wetlands.

Diagnostic Characters: Douglas firs are easy to recognize by their “groovy” bark, pointed buds, and cones with 3-pronged bracts. Young trunks or branches often have “resin blisters,” that are easily ruptured; this sticky pitch is very difficult to wash off your hands!

Groovy Bark of Douglas Fir

“Pointy” buds of Douglas Fir

Douglas Fir in winter

In the landscape: Douglas fir is a majestic tree. It will grow in extremely dry to moist sites. When growing in a container, it is often spindly and not very attractive, but once it is planted in the ground, out in the open, it will quickly develop into the familiar, pyramidal Christmas tree shape. On the down side, it is often the bane of golf course and park workers after a windstorm. Because it is a fast growing tree, the new wood is relatively weak, and broken branches fall to the ground and must be picked up before grass can be mowed. For the same reason you may wish to avoid planting it next to buildings and other highly maintained areas such as courtyards and thoroughfares.

Douglas fir trees grow with a “central leader.” This is what forms the single trunk. As with most conifers, it is important never to “top” these trees. In young trees, it is possible to prune or train damaged or disfigured trees so that they have only one leader. Trees that are allowed to have more than one leader, besides being unsightly, will have a weak point where the two leaders emerged; creating a likely spot for a future break.

Male & female cones

Phenology: Bloom Period: March-June, earlier in southern coastal areas, later at high elevations, interior and northern stands. Cones mature in mid to late September, seeds are dispersed soon after.

Propagation: Seeds of Douglas Fir have about a 40% germination rate with a stratification period at 40ºF (4ºC) for 60 days. Seeds remain viable 1-2 years. Volunteers in the landscape may easily be transplanted.

Use by People: The Douglas fir is the most important timber tree in the United States. It is used for dimensional lumber, plywood and many other building materials as well as paper products. It was mostly used for firewood by native peoples but the wood was also used for tools such as spear and harpoon shafts. Today it is still commonly used for firewood and is well known as a popular Christmas tree.–See Selecting a Christmas Tree on my sister website, habitathorticulturepnw.com !

Use by Wildlife: Douglas Squirrels and other rodents eat the small, winged seeds found inside Douglas Fir cones. Pine Siskins and Crossbills and other birds also eat the seeds. Browsers, such as White-tailed Deer will eat the foliage and twigs in the winter. The needles and male cones are an important winter food for Blue Grouse

The Mouse and the Douglas Fir

Douglas Fir cone with 3-pronged bracts

There are two versions of a Native American Myth relating the story of a frightened mouse looking for someplace to hide. In one version the mouse is trying to evade a fox, in the other the mouse is trying to escape a forest fire. In both versions, the mouse tries to hide in a Douglas Fir cone. The mouse was successful in evading the danger in both stories. To this day, when you look closely at a Douglas Fir cone, the mouse’s back legs and tail are still visible beneath the cone’s scales!

Links:

WTU Herbarium Image Collection, Plants of Washington, Burke Museum

E-Flora BC, Electronic Atlas of the Flora of British Columbia

USDA Forest Service-Fire Effects Information System

Virginia Tech ID Fact Sheet + Landowner Fact Sheet

Native Plants Network, Propagation Protocol Database