Cornus florida Seeds | Flowering Dogwood
LATIN NAME: Cornus florida
COMMON NAME: Flowering Dogwood
Plant Profile
Flowering dogwood is the tree that defines spring in the eastern United States, and the first thing to say about it is that the white petals are not petals. They are bracts, four of them, surrounding a small central cluster of true flowers, and they open flat like a star. The effect in late April, under a canopy of oaks and hickories, is of a layer of white cloud at head height. Leaves are ovate, pointed and strongly veined, turning a deep red-purple in autumn, and the fruit is a cluster of glossy red berries that birds take as soon as they ripen. It grows five to ten metres, often wider than tall, with a flat-topped, layered crown and a bark that breaks into small square blocks, like alligator skin. It is an understorey tree of acid woodland, and it wants shade for part of the day and leaf mould at its feet.
Science & Biotechnology
Cornus florida is a diploid, 2n = 22, and it is one of the dogwoods whose ‘flowers’ are pseudanthia: the four showy bracts are modified leaves, and the actual flowers are the tiny greenish cluster in the centre, which is why the tree can be pollinated by small bees and flies that land on the bracts. The red berries are drupes with high lipid content, and they are dispersed by thrushes and other migrants in autumn. The species is severely affected by dogwood anthracnose, caused by Discula destructiva, a fungus that arrived in the 1970s and kills trees in cool, moist, shaded sites, particularly above six hundred metres. It is also the host of the dogwood borer and of a powdery mildew. The wood is extremely hard and dense and has been used for mallets, shuttles and tool handles. It is not the medicinal dogwood of Chinese pharmacy, which is Cornus officinalis.
Uses & Benefits
Its use is ornamental, and in that role it is one of the best small trees of the temperate world: a specimen for a woodland edge, a lawn, or a courtyard, with four seasons of interest in flower, leaf, fruit and bark. The autumn colour is reliable, the berries feed migrants, and the layered habit reads well against a wall. The wood is hard enough for turnery and was once used for golf club heads and weaving shuttles. The bark has a bitter astringent record in American folk medicine, used for fevers and as a wash, but it is not the source of Shan Zhu Yu, which is Cornus officinalis, and the two should not be substituted. The tree’s biggest practical problem in the garden is anthracnose, and the answer is site selection rather than chemicals.
Growing from Seed
Sow fresh seed in autumn, after removing the fleshy red coat, and leave the pots outdoors for two winters, since the seed has a double dormancy; germination is often in the second spring. Use an acid, leaf-mould-rich mix, sow two centimetres deep, and keep the pots moist and shaded. The seedlings are slow for the first two years and need shade, so grow them on in a frame or under a lath. Plant out at thirty to forty centimetres, in a site with morning sun and afternoon shade, in acid soil with plenty of organic matter, and mulch with leaves. Do not plant where dogwoods have died of anthracnose. Water in dry summers, keep the trunk clear of mulch, and avoid wounding the bark, which is the entry point for borers.
Our Take
A first-rate small tree for a woodland edge, grown for the spring bracts and the autumn colour. Give it acid leaf mould and afternoon shade, and keep it away from anthracnose sites.
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