Plant of the Month (January) : Redosier Dogwood – Cornus sericea

 

Redosier dogwood (Cornus sericea): provides good fall color!

We’re truly experiencing winter this time of year; snows have turned Mother Nature’s Montrose Garden into drifts of white. Pretty, but perhaps a little too monochromatic!  When brightening up a winter garden, plants with interesting shapes and colorful bark can be a godsend.  And our Plant of the Month, Redosier dogwood, is one of the best for colorful bark.  The scientific name is pronounced KOR-nus  sir-IH-see-uh.

Redosier dogwood has gone by many names through the years.  Some common names are American dogwood; Red willow and Red brush; Red, Redstem or Red-twig dogwood; Creek, Rose, Silky, California, Western or Poison Dogwood;  Waxberry, Red-osier and Red-stemmed Cornel; Red Rood; Harts Rouges; and Dogberry Tree. 

The species has also been given a number of scientific names, including Cornus alba, Cornus baileyi, Cornus instolonea, Cornus interior, Cornus stolonifera, Swida instolonea, Swida stolonifera and Swida sericea.  Subspecies and varieties have also been proposed for many of the above.  For example, the Redosier dogwood of Western Colorado was formerly known as Cornus stolonifera var. coloradensis.  Taxonomists now lump all the above into the species Cornus sericea, with two subspecies: Cornus sericea subsp. sericea (the more common form) and Cornus sericea subsp. occidentalis (limited to WA, OR and CA).

Why so many names?  Perhaps one reason is because type specimens were collected over a relatively long period of time (Linnaeus named some in the 1700’s). Another reason is the broad species range, extending over much of North America (with the exception of the southeastern and southern plains states). Not surprisingly, morphologic (appearance) variants occur across this extensive range. This is yet another factor responsible for the different species, subspecies and varietal names.

The last point has some relevance for those desiring a Redosier dogwood appropriate for their local area.  Several reasons support choosing locally-sourced plants.  First, they have the appearance of the local, wild-growing type and so ‘look appropriate’.  Second, they may be better suited to local growing conditions than those from distant source plants.  Finally, planting locally-sourced plants helps support the nurseries that grow and sell locally-native plants.

Redosier dogwood (Cornus sericea): young plant

Redosier dogwood is an upright, woody, winter-deciduous shrub.  If you live in the West, you’ve likely seen it growing along creeks and other moist places at higher elevations. It generally reaches heights of 6-10 ft [2 to 3 meters], though in some parts of the country it may grow to 12-20 ft.  In Colorado, our native variants are in the 6-8 ft. range.

Cornus sericea is a clump-forming shrub, sending out new shoots from the ground and attaining a width of 8-10 ft. or more.  The bark and twigs are a lovely bright red to burgundy in late fall and winter.  It is the bark and growth habit that make this plant a valuable winter color source in the garden.

Redosier dogwood (Cornus sericea): foliage

From spring to fall, Redosier dogwood is an attractive, bright-green shrub. The leaves are simple, opposite and oval to oblong in shape (above). In some variants, the leaves may be up to 4 inches long; in Western Colorado, the leaves are closer to 2 inches. The leaves are darker above and lighter beneath due to plant hairs (trichomes).  The leaves turn shades of yellow, red or purple in fall, with fall colors varying by plant and yearly weather.  In terms of its foliage, this shrub is pretty in spring-summer, but spectacular in fall-winter. 

Redosier dogwood (Cornus sericea): fall foliage

But that’s not all….   Cornus sericea is, after all, a Dogwood.  And Dogwoods are known for their attractive flowers.  Redosier dogwood is not the showiest species, but it does produce sprays of lovely white flowers from June to August (or even into September with a little water).  The flowers grow in dense, flat-topped clusters (technically called cymes). The flowers themselves are small - 0.08-0.12 inches (2-3 mm) – with four petals typical of the Dogwood family (below).  The color ranges from bright white to creamy-white, and the flowers are sweetly scented. 

Redosier dogwood (Cornus sericea): flowers

Redosier dogwood (Cornus sericea): young fruits

The flowers attract many types of pollinators, from native and Honey bees, to butterflies, moths and flower flies.  The resulting fruit is a small (1/4 to 1/3 inch) berry (technically a drupe) with a large seed.  The fruits start green, maturing to white or a light blue (the Colorado variants are bluish). The fruits remain on the shrub into winter, providing a cold-weather source of food for fruit-eating birds.

All in all, Redosier dogwood is an excellent habitat shrub, with the pollen and nectar just the beginning.  The fruits attract a wide variety of birds, including bluebirds, catbirds, finches, flickers, flycatchers, grosbeaks, kingbirds, magpies, mockingbirds, orioles, robins, European starlings, tree swallows, tanagers, thrushes, vireos, pine warblers, cedar waxwings and woodpeckers. Game birds who eat both the fruits and buds include grouse, ringnecked pheasants, band-tailed pigeons, greater prairie chickens, quail, and wild turkeys. [1] In addition, the dense foliage provides excellent nesting sites for birds.

Desert Cottontail: one of many mammals that
 eat Cornus sericea

In the wild, Cornus sericea fruit and foliage are eaten by black bear, beaver, rabbits, raccoons, skunks, squirrels, chipmunks and other smaller mammals. Deer, elk, Mountain goat, and moose also browse the twigs and foliage.  [2]   And where ever it grows, people have made use of Redosier dogwood.

The fruits are tart and can make you sick if eaten in large quantities.  None-the-less, they were traditionally used as a relish or dried and eaten – alone or mixed with sweeter berries.  The plant also has a history of use as a natural medicine, although the uses seem less specific than for many other medicinal species. [3-5]  Both the bark and leaves were sometimes used for smoking, often mixed with native tobaccos.

The branches of Cornus sericea were traditionally used to make a number of useful products and utensils including toothbrushes, bows and arrows, digging sticks, pipe stems, drumsticks, tipi stakes and pins, slingshots, weaving shuttles, cooking and drying racks, and kettle hangers. The species was widely used in basket-making, and is still gathered for this use today.  The bark retains its red color if collected in spring and different bark colors were often utilized in basketry patterns.  The bark can also be used as a dye-stuff.

Redosier Dogwood (Cornus sericea): plant where it
has room to grow.

Redosier dogwood is fairly easy to cultivate in the garden.  It grows in USDA Zones 2-8 and tolerates many soil textures.  It can be grown in soils with pH 5.0 to 8.0, though it probably likes neutral soils best.  And plants tolerate full sun to part-shade.

They do like water and grow best in soils that are saturated at least part of the year. But warm, moist weather can promote fungal diseases; drier climates or planting in an area with good air circulation is recommended.  Once established, Cornus sericea can get by on deep weekly summer water – perhaps even less in denser soils.  It actually does better if soils are left to dry out in late summer and fall, mimicking natural seasonal conditions.

Redosier Dogwood (Cornus sericea): flower buds

Redosier dogwood requires only minimal maintenance.  This species is a spreader, so plant it where it can expand a bit.  If shoots appear where unwanted, cut them off at the root with a sharp shovel.    Routine pruning is not necessarily required.  But removal of the oldest 20% of stems in early spring (cut back to the ground) promotes good winter color.  Alternatively, the entire plant can be cut to the ground (coppiced) every 3 to 4 years to rejuvenate.  Either of these methods keeps the plant healthy as well as attractive.   The goal is to mimic the natural ‘pruning’ done by animals in the wild.

Redosier Dogwood (Cornus sericea): fall leaf color

So, why consider Cornus sericea for your home garden?  First, it’s a wonderful habitat plant, providing food, shelter and nesting sites for a wide range of creatures. It’s also the perfect shrub for places that stay a bit moister than the rest of the garden – perhaps on the north side of a fence or building.  If you have a stream or pond, Redosier dogwood will be right at home there.  It also works in a rain garden or infiltration swale, and does a nice job of stabilizing slopes and banks.  

Redosier dogwood makes a nice hedge or hedgerow shrub, with its green foliage, fragrant flowers and fruits.  It’s prized for winter color, often when contrasted with evergreen shrubs such as junipers.  Or pair it with its natural associates: aspen (Populus tremuloides), birch (Betula spp.), Wood's rose (Rosa woodsii), wild currants and gooseberries (Ribes spp.), hawthorne (Crataegus spp), maples (Acer species), ash (Fraxinus species), Western sycamore (Platanus racemosa), cottonwood (Populus species), willow (Salix species), wild honeysuckle (Lonicera species) and wild grape (Vitis species)  

If you are a basket-maker or twig artist, several Cornus sericea shrubs will supply you with materials every year. You might even want to put the wood to some of its traditional practical uses!

If you need an Cornus sericea with specific characteristics (size; leaf size; bark color) there are a number of cultivars available from traditional shrub nurseries.  So the only question is: do you have a place for this lovely native shrub?

 

For a gardening information sheet see: Gardening sheet cornus sericea (slideshare.net)

For more pictures of this plant see: coming in 2021

For plant information sheets on other Western U.S. native plants see: http://nativeplantscsudh.blogspot.com/p/gallery-of-native-plants_17.html

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1. https://plants.usda.gov/plantguide/pdf/cs_cose16.pdf
2. https://mpgnorth.com/field-guide/cornaceae/red-osier-dogwood

3.       https://medivetus.com/botanic/cornus-sericea-red-osier-dogwood-medicinal-uses/

4.       Harrington, H. D. 1967. Edible native plants of the Rocky Mountains. University of New Mexico Press, Albuquerque, New Mexico.

5. Kershaw, L. 2000. Edible and medicinal plants of the Rockies. Lone Pine Press, Edmonton, Alberta.

 

 

We welcome your comments (below).  You can also send your questions to: monaturesmontrosegarden@gmail.com