The flowering dogwoods are a little behind schedule this year, coming into flower now, about two weeks late, delayed by a cold and wet spring and early summer. These are plants of warm climate in North America and Japan. The flowering dogwoods are iconic plants in their native lands and it is easy to see why.
Called flowering dogwoods because of their showy flowers in early summer, they are related to the dogwoods grown for brightly coloured winter bark. The winter bark dogwoods have flowers too but they are so insignificant as to be hardly noticeable. There is no missing their flowering cousins though, they cover themselves with sheets of white or pink flowers, every bit as good as the splendid magnolias of April and a perfect follow-on.
The best of the various kinds is the kousa dogwood, Cornus kousa, from Japan. At least, Japan has an island climate, warmer than here but its seasons are not as dramatically different as continental North America. In any case, the kousa dogwood is more at home here than is the North American branch of the family. The North American dogwoods are not at all happy here. They are likely to be good this year after the great summer of last year, but they need a summer like that every year to flower well.
The kousa dogwood is more adaptable and much more consistent, although it too puts on a better show in the year after a good sunny summer when it lays down the flower buds for the following year. It promises to be superb this year, as the flowers are now in their final week of unfurling.
The flowers themselves are curious. Each flower is formed of four petal-like bracts and bracts are longer lasting than true petals which are more delicate. The bracts start out green, growing larger and turning white when fully grown, or pink in some varieties. One of the best is the pink-red 'Satomi'. It carries sweeps of hundreds of flowers sitting on top of the branches. The tree only reaches three or four metres tall in general and it could easily be grown as a really decorative tree for small gardens.
The true flower is a group of tiny florets at the centre of the bracts and this later ripens to make a red fruit which itself is decorative. In autumn, the leaves slowly turn to rich red and yellow shades, a second season of interest. It likes neutral to acid soil, open and well-drained. Limy soil should be improved with lots of organic material at the planting stage, and annual mulches of decayed leaves to acidify the soil and make it suitable for this lovely plant.