General Description | Cornus amomum is a native woody shrub of the Cornaceae family, is often found in swamps, hence its adjacent name swamp dogwood, though is most commonly known in North America as silky dogwood. Cornus amomum is often distinguishable in the swamps due to its creamy white flowers in the spring and porcelain blue drupes in the summer, though its dark red
twigs make it most distinctive. Cornus in Latin means ‘horn’, in reference to the hardiness of its wood. |
ID Characteristic | Three general identification characteristics for Cornus amomum would be their creamy white, flat topped flowers, their attractive brilliant blue berry fruit when ripe, and that their twigs are reddish-brown in colour, with older bark a brown grey. |
Shape | The shape and orientation of Cornus amomum is semi-erect, with dense summer foliage and moderate winter foliage. Active growth periods occur in the spring and summer seasons. If growth is left uncontrolled, thickets may form. The plant is multi-stemmed, rounded, open, and
can grow 2 - 3 m in height. |
Landscape | Cornus amomum in nature is typically used as an understory tree; however, they are mainly used in commercial use in urban plantings for homes and backyards. As such, they are routinely available commercially. When used, they are often placed in run off areas or water collection
spots in a landscape, placed along banks and slopes, garden beds and borders, ponds and streams, and rain gardens. These trees are typically sought out for their attractive ornamental value, as not much practical use is derived from them outside of medicinal and tobacco use from Native American tribes. Their berries are not sold as a product. They are not grown for use of lumbar, pulpwood, or veneer, mainly just nursery products. |
Propagation | Cornus amomum can be propagated through layering, seed, stem cuttings and bare roots. Seed propagation should begin as soon as the plant is ripe. Should either be sown in a cold frame or an outdoor seed bed. As soon as seedlings are large enough to handle, they should be moved from cold frame to individual pots for greenhouse use during their first winter, being planted in the spring after the last expected frost that year. Cuttings of half-ripe side shoots should be sown in a cold frame between July and August. Cuttings from mature wood should be sown in a cold frame in autumn. Layering should take place between June and July. Seedlings often take about 9 months to grow. Requires cold stratification, tough scarification, followed by warm stratification before the required cold stratification can also improve seed growth. For germination, the seed should be separated from the flesh. Germination can take 18 months or longer. |
Cultivation | Cornus amomum is exceptional at growing in moist wetlands and naturalized areas due to its preference to wet and acidic soils. Cornus amomum is quite proficient at erosion control as it is resistant to honey fungus. Soil types preferred include, chalky, clay, loam, and sand. Soil pH levels can range between 5 and 7 and can be found in acidic, to alkaline, to neutral pH soils, though acidic soil is most preferred. Soil should be moist, but well-drained. Cold stratification is also required. |
Pests | Cornus amomum is highly susceptible to the dogwood borer, which can cause wilted leaves, dying branches, and holes in the bark. When affected, Cornus amomum can die within just a few seasons if not treated. Dogwood sawfly is also an issue, as the larvae will feed off the leaves. If left out of control, entire branches can be defoliated by the insect. The plant is also susceptible to leaf spot, crown canker, and blights. If regular maintenance is neglected, the plant can form thickets. |
Notable Specimens | The Cornus amomum specimen can be observed in the Shaw Nature Reserve, found in Gray Summit, Missouri, located in the United States of America. |
Habitat | Cornus amomum is typically found along swamps, streams, ponds, and lakes. Cornus amomum performs best in well-drained, acidic soils that are typically medium to wet. Roots need to be kept cool and damp during the summer season, and grow most often in full sun to partial
shade, though full shade can be tolerated. Cornus amomum is native to Eastern North America, and can be found all the way from states such as Florida and Texas, to provinces such as Newfoundland and Ontario. |
Bark/Stem Description | Bark is light grey in colour, with smooth, thin, bark. Stem colours range depending on age. For young stems, colour ranges from green, to red, to purple, and to burgundy. Older stem colours range from brown, to copper, to purple, to red, and to burgundy as well; overall a darker
tinge over time. The stem is not aromatic, with conspicuous lenticels, and it is covered in dense fine hairs. Older branches develop brown, vertical lenticels. Pith is a dark brown. |
Flower/Leaf Bud Description | Flower buds are terminal and relatively small, starting off green before turning creamy white like their flower. Buds are valvate, with abutting edges, they are oblong in shape and covered with hair. Leaf buds are also small in size, starting out light green in colour before turning dark
green. Leaf buds are also pubescent and valvate. |
Leaf Description | Leaves are smooth in texture, opposite, elliptical to ovate in shape, and acutely veined with silky greyish white or brownish hairs along veins. Leaves typically grow from 5 - 12 cm long. In the spring and summer, leaves appear a dark green with a paler green underside, with
autumn foliage producing typically dark greens and browns -- though sometimes leaves can also become a purplish red. Petioles are typically 1 - 1.5 cm long. |
Flower Description | Individual flowers have four petals, four sepals, and four long stamens. The flowers are creamy white in colour, with cyme inflorescence, arranged in tiny, flat-topped clusters. Flowers are 5 cm wide. Flowers from May to July, attracting many birds, with mainly insects as their
pollinators. Other attractors include azure butterflies, song birds, small mammals, and specialist bees. |
Fruit Description | The fruit which is produced can be eaten raw or cooked, with the fruit typically growing to a size of 1 cm in diameter. Cornus amomum produces berry-like drupe fruit which becomes a blue colour when ripe, white when developing, and produces a green seed. Flowers blooming from early to late spring turn into berries in summer. The fruit and seed produced is
low in abundance, arranged in drooping clusters. Attractors for their fruit include songbirds, ruffed grouse, quail, foxes, skunks, black bear, and more wildlife creatures in their surrounding habitat. |
Colour Description | Spring and summer blooms are creamy, typically white clusters (sometimes with a slight yellow tinge). Produces a dark brown pith (between one to two years) and dark red/purple twigs. Older bark becomes a grey colour. Leaves are a mid to dark green colour in spring and summer, green to brown in autumn, though sometimes can become a reddish-purple. Flowers
from spring turn to white berries which then ripen into a porcelain-blue colour. |
Texture Description | The texture of Cornus amomum is coarse, with vertical, shallow fissures and lenticels, turning a brownish grey with age. |