Cornus amomum subsp. obliqua
Common Name: swamp dogwood
Type: Deciduous shrub
Family: Cornaceae
Native Range: Eastern and central North America
Zone: 4 to 8
Height: 6.00 to 12.00 feet
Spread: 4.00 to 10.00 feet
Bloom Time: May to June
Bloom Description: Yellowish-white
Sun: Full sun to part shade
Water: Medium to wet
Maintenance: Medium
Flower: Showy
Attracts: Birds
Fruit: Showy

Culture

Grow in average, medium to wet, well-drained soils in full sun to part shade. Prefers moist, organically rich, slightly acidic soils in part shade. Tolerates close to full shade. Benefits from a 2-4” mulch which will help keep roots cool and moist in summer. Branches that touch the ground may root at the nodes. When left alone, this shrub may spread to form thickets.

Noteworthy Characteristics

Cornus amomum subsp obliqua is synonymous with and formerly known as Cornus obliqua. It is a medium-sized deciduous shrub that is typically found in moist lowland areas, swamp borders, floodplains, shrub wetlands, wet meadows/prairies and along streams and ponds in Eastern and Midwestern North America (New Foundland to Ontario south to Oklahoma, Arkansas and Virginia). In the words of the Royal Horticultural Society, this subspecies primarily differs from species plants by having "a looser habit". Twigs and leaf undersides have silky hairs, hence the common name of silky dogwood. This dogwood typically grows to 6-12’ tall with an open-rounded form. Tiny yellowish-white flowers (showy petal-like white bracts are absent) in flat-topped clusters (cymes to 2.5” across) bloom in late spring to early summer. Flowers give way to attractive blue to white berry-like drupes that ripen in late summer (August). Birds are attracted to the fruit. Oval to elliptic, medium green leaves (2-3” long) have conspicuous veins. Attractive fall color is usually absent. Twigs are purplish brown in spring, and have a distinctive brown pith.

Genus name comes from the Latin word cornu meaning horn in probable reference to the strength and density of the wood. Cornus is also the Latin name for cornelian cherry.

Problems

No serious insect or disease problems. Plants are susceptible to scale. Additional insect pests include borers and leaf miner. Infrequent disease problems include leaf spot, crown canker, blights, root rot and powdery mildew.

Garden Uses

Good shrub for moist to wet areas of the landscape. Not overly ornamental. Somewhat wild and unkempt for placement in prominent areas. Good selection for moist woodlands, naturalized areas, along steams/ponds or for erosion control.