Description
Cornus – Cornel – Dogwood –
There are about 45 species of deciduous and evergreen shrubs and small trees, and 1 or 2 woody based herbaceous perennials, in this genus. They occur in grassland, thickets, woodland, rocky slopes, and swamps, mostly in Northern Temperate areas. The usually smooth edged, opposite, sometimes alternate leaves are ovate-lance shaped to broadly ovate, and mid to dark green with prominent, inward curving veins. Small star shaped flowers, come in greenish, yellowish or purplish shades are borne in terminal cymes, with or without bracts, in dense umbels with yellowish bracts that fall as the flowers open, in dense clusters with conspicuous white or pink bracts. Those borne in cymes or umbels are followed by loose clusters of berries, those borne in clusters are followed by tight clusters of berries or are united into compound, fleshy fruits.
Dogwoods are grown for their showy bracts, elegant habit, fruits, and colorful autumn leaves, some are effective specimen trees or shrubs, especially in a woodland garden. Those with colorful winter shoots, sometimes coppiced or pollarded, are useful for many situations, from a shrub border to a waterside garden. The fruits of some species may cause mild stomach upset if ingested, contact with leaf hairs may irritate skin.
Grow in full sun or very light shade, in neutral to acidic soil that’s rich, fertile, well drained soil, though some of the multi stemmed shrub species will grow well in boggy ground.
Prone to spot anthracnose (dogwood blight, powdery mildew, Discula blight, crown canker, bacterial leaf spot, mushroom root rot, twig borers, weevils, sawfly, scale insects, aphids, leafhoppers, root knot nematodes, and thrips.
C. alternifolia – Green osier – Pagoda Dogwood – This deciduous tree or multi stemmed shrub found on dry slop in Eastern North America grows 20-25′ feet tall and 20′ feet wide. From spreading, tiered branches it carries alternate, ovate-elliptic, pointed, mid green leaves, to 5″ long, turn red and purple in autumn. In late spring or early summer it bears small cream to white flowers carried in flat cymes, to 2″ across, followed by spherical blue-black fruit on red stalks. Best in moist soil in partial shade.
‘Argentea’ – ‘Variegata’ – grows 10′ feet tall and 8′ feet wide and is a tiered shrub or small tree with white edged leaves, to 3″ long, but is weak growing.
Zones 4-8
