Cornus amomum
If you’re searching for a plant to liven up a particularly soggy spot in your yard, consider silky dogwood (Cornus amomum).
This species is cold hardy, remarkably pest and disease resistant, and very easy to grow.
As long as you can provide full sun and consistent moisture, this unfussy, medium-sized native shrub might just be right for your landscape.
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Silky dogwood is found growing wild in wet areas as far north as Ontario and Maine and south through Missouri and Florida.
Thriving in average to rich, damp, freely draining soil, C. amomum naturally occurs in swamps, floodplains, wetlands, and around streams and ponds.
In our guide to growing dogwood, we introduce the Cornus genus and the wide variety of different species.
This guide focuses on silky dogwood, a native, low-maintenance shrub.
Here’s what I’ll cover:
What You’ll Learn
Growing up to 12 feet high and six feet wide, this shrub can appear somewhat gangly and unkempt.
Spreading fairly rapidly, silky dogwood often produces roots where low branches touch wet soil, creating dense thickets.
Leaves are fairly nondescript, oval-shaped, sporting the looping venation characteristic of many Cornus species. The hairy undersides of the leaves are what give the plant its common name.
In May and June, clusters of small, creamy white or yellowish blossoms adorn the plant, attracting a variety of insects from bees to butterflies.
Towards the end of summer and beginning of fall, pollinated flowers give way to cobalt blue berries.
This is undoubtedly when silky dogwood is at its most ornamental – when a little early fall color comes creeping into the leaves and highlights the rich, dark, clusters of berries.
Quick Look
Common name(s): Silky or swamp dogwood
Plant type: Woody shrub
Hardiness (USDA Zone): 5-8
Native to: North America
Bloom time / season: Spring flowers, fall berries
Exposure: Full to part sun
Soil type: Moist, fertile, well-draining
Soil pH: 5.5-7.0, slightly acidic to neutral
Time to maturity: 5 years
Mature size: 6-12 ft wide x 12 ft high
Best uses: Erosion control, wetland plant, windbreak, wildlife garden
Taxonomy
Order: Cornales
Family: Cornaceae
Genus: Cornus
Species: Amomum
Hardy in Zones 5 to 8, C. amomum can withstand all but the most frigid of conditions.
It’s also quite happy with a bit of flooding or to dry out from time to time. Silky dogwood is resilient, attractive, and ecologically important.
Given plenty of water, sunshine and room to grow, this hardworking plant will pay its way, attracting hordes of pollinators in summer and flocks of birds in the fall.
How to Grow
The real beauty of this North American shrub is its ability to produce blossoms, fruit, and attract wildlife without you having to lift a finger.
Plant it somewhere you don’t have to worry about watering and simply sit back and let it run wild.
This versatile wetland species does not require fertilization and needs no pruning, either.
The main ingredients you need to grow a hearty, happy, silky dogwood are sun, fertile soil, and water.
Light
Silky dogwood prefers a full sun to partial shade location. It can tolerate a fair bit of shade, but you’ll see less prolific blooming.
Consider its preference for full sun before you start packing it in with other plants.
Soil
Although this species prefers the organically-rich, marshy shores of a wetland or stream, C. amomum can tolerate drier soils once established.
Fertile, well-draining, consistently soil with an acidic to neutral pH of 5.5 to 7.0 is ideal.
Water
This species is very tolerant of wet, boggy, poorly drained soils, and consistent moisture is non-negotiable.
When established, the shrub will be okay with short dry spells but any extended drought will require supplemental irrigation.
If you do choose to locate silky dogwood somewhere that dries out periodically, make sure to heap a good three inches of mulch or compost on top of the root zone every spring and summer.
This extra layer of insulation will help trap moisture. If it doesn’t rain heavily at least once a week, water deeply.
Where to Buy
You can typically find silky dogwood at plant nurseries or online retailers that specialize in native plants.
There aren’t any cultivated varieties of this species available so it’ll generally be listed as silky dogwood.
You will sometimes come across swamp dogwood (C. obliqua) which was previously considered to be a subspecies of C. amomum. It’s quite similar to silky dogwood and often difficult to tell them apart.
You can find bare roots and plants in #3 containers available at Nature Hills Nursery.
Propagation
You can propagate silky dogwood from seed, stem cuttings, or transplanting nursery starts.
Starting this shrub from seed can be quite unreliable, and may be better left to seasoned propagators.
From Seed
If you are collecting your own seed you’ll face the tricky task of removing the pulp from the seed prior to sowing.
This tricky, sticky work is typically done by bird, reptilian, and mammalian stomachs.
The best way to do this is to soak the fruits in warm water for a day or two.
The fleshy rind can then be peeled away from the seed with the help of a coarse sponge, some softened sandpaper, or even by removing the blades of a blender and pulsing the fruits in the water for a few cycles.
When they are clean, allow the seed to dry on a paper towel.
The seeds require a cold period known as cold stratification to kickstart germination.
To achieve this, you can either place your prepared seed in a bag filled with moistened vermiculite and set it in the fridge for 60 days or sow in trays outdoors in fall and allow nature to handle the stratification.
If you choose to stratify your seeds in the fridge, start the process so that they’ll be ready to sow in spring, close to your last frost date.
To sow seeds, prepare a flat of moist potting soil and scatter them across the surface. Poke each seed down into the soil so it is buried about a quarter of an inch deep.
If you sow in fall, place your flat outdoors in a location protected from temperature extremes and high winds. Keep the soil moist, but not soaking wet. Seeds will typically start to germinate in spring.
After germination, keep the soil consistently moist but not waterlogged. When a month or two has passed, thin your seedlings to an inch apart.
In mid to late summer, you can pot up the most robust seedlings into four-inch pots and continue to care for them until the following spring when you can transplant out into the garden.
From Stem Cuttings
Many of the species in the Cornus genus will root from cuttings buried directly in the ground.
Silky dogwood, and its cousins red twig dogwood (C. sericea) and gray dogwood (C. racemosa) are all capable of being propagated this way.
Cuttings are best taken in the fall after leaf drop.
Select a long, straight, healthy twig with no wounds or blemishes on the bark. Using a clean, sharp pair of pruners, cut a 24-inch-long piece of stem, angling your cut at a 45-degree angle.
Plant the cut end six to eight inches into very moist soil. It helps sometimes to use a sturdy stick, or the handle of a garden tool, to make a guide hole. This way you can ensure the stem doesn’t break as you slide it into the ground.
Moist soil is essential for this method of propagation to work. If your soil dries out over the winter or spring, make sure to water thoroughly.
Leaf development in spring will let you know your cuttings have rooted and are well on their way to becoming large, sturdy shrubs.
Softwood Cuttings
You can also propagate silky dogwood from softwood cuttings taken in the summer, after flowering is finished.
Prepare a four-inch pot with equal parts potting soil and vermiculite. Make sure the substrate is tamped down well and thoroughly moistened.
Select several pieces of pliable growth, about three to five inches in length. With a sharp, clean pair of scissors, snip each cutting just below a pair of leaf nodes. Remove all the leaves from the lower half of the stem.
Bury the bottom two inches of the cuttings into your prepared pot, leaving two to three leaf nodes above the soil. Use a pencil to make guide holes. You can grow three cuttings in each four-inch pot.
Create a tent around your pot with a clear plastic bag to make a modified humidity dome. Keep the soil consistently moist, but not waterlogged.
In six to eight weeks, your cuttings should have rooted.
After a month or so of root growth, your new silky dogwood plants can be set out in the garden.
Transplanting
To transplant your cuttings, seedlings, or purchased nursery starts, the process is pretty simple.
Dig a hole a little wider than the root ball and just as deep. Silky dogwood really loves moisture, so I personally like to drench the root ball before burying it.
Set the plant in the hole and cover the roots with soil, tamping it down as you go. Water in well.
Space plants six to 10 feet apart to allow for mature spread.
Managing Pests and Disease
Pests and diseases that trouble this tough, wetland species are few and far between.
Growing your shrub in optimal sunny, wet conditions will help it remain vigorous and healthy.
Branches of young plants can sometimes be nibbled on by little rodents, like muskrats, especially if they’re planted close to water.
Erecting a small, two foot tall cage of chicken wire around your new plant can help protect it from damage while it’s becoming established.
Pests
Although plenty of creepy crawlies may choose to munch on your silky dogwood, few will actually damage your plant.
In fact, I recommend leaving native insects alone to feed on your plant as needed.
The only problems you may come across are scale, leaf miners, and borers. Unless the infestation is severe, you don’t need to do anything.
Read our guide to dogwood pests to learn more.
Disease
Silky dogwood is somewhat susceptible to a few mild fungal diseases. None of these issues are particularly problematic and can generally be managed fairly easily.
Leaf Spot
The term “leaf spot” describes a variety of blemishes and lesions on the foliage, generally as a result of fungal infection.
You may see black or brown discoloration and the lesions can be circular or splotchy and irregular.
There’s not a lot you can do to prevent this issue, as fungal pathogens are generally prevalent in the damp conditions favored by this species.
Happily, leaf spot is almost never serious, though it can cause early leaf drop in the case of a severe infection.
If your plant suffers from leaf spot one year the chances are good that it will be perfectly fine the following year.
Powdery Mildew
Like leaf spot, powdery mildew is caused by numerous different fungal pathogens. This condition is characterized by a white to gray powder coating the upper surfaces of the leaves.
In severe cases it can cause leaf drop.
Powdery mildew is primarily an aesthetic problem. An established, healthy specimen will tolerate an infection of powdery mildew very well.
You can learn more about powdery mildew here.
Our guide to common dogwood diseases has more information.
Rugged and Reliable
Fortunately for the laidback gardeners among us, silky dogwood truly takes care of itself.
Tolerant of variable moisture levels, impervious to extreme cold, and barely bothered by pests and diseases, this species will attract beneficial insects and provide the birds with tasty berries.
Give this species the moist, sunny conditions it prefers, step back, and let it prosper.
Do you grow silky dogwood? Please tell us how you use this wonderful species in your own garden. Comments and questions are always welcome, too!
And to learn more about growing dogwood in your landscape, check out these guides next:
