The magnificent Okame cherry breaks the dreary grip of late winter with an outstanding two- to three-week display of rosy pink blossoms. This hybrid small flowering cherry was developed in England, created by crossing two Asian cherry species. Full sun and moist and fertile soils encourage healthy growth and abundant blossoming.
The Okame cherry is a man-developed hybrid plant. In early 20th century England, noted cherry tree enthusiast Captain Collingwood Ingram experimented with creating a cherry with excellent tolerance of winter cold and tremendous flowering. The seedling 'Okame' resulted from fertilizing the female flower of a Fuji cherry (Prunus incisa) with the pollen from a Taiwan cherry (Cerasus campanulata).
Sources in the 20th century published the botanical name as Prunus x incisa 'Okame'. This name is considered synonymous with, but is not preferred to, the modern name of Prunus 'Okame'.
Mature Form and Height
When young, the Okame cherry has an upright, vase-like shape. As the tree matures, the overall form of the small tree becomes more rounded. This cherry will grow to a maximum height of 20 to 30 feet, with a canopy spread of 12 to 20 feet.
The glory of the Okame cherry is the abundance of rosy pink flowers in late winter and early spring. It is often regarded as the first cherry tree to flower in the landscape, often flirting with subfreezing late winter temperatures as the flowers open. The flowers have five petals and are attractive as pollen and nectar sources for bees. Although the flowers are pink, there are castings of reddish rose or lavender when the blooms are seen en masse on the branches. The flowering season lasts two to three weeks.
After flowering, the deep green foliage appears and extends into autumn. In hot, long summers, the foliage often becomes bronzed, more so if conditions are dry. As autumn weather brings sunshine with cool nighttime temperatures, the foliage turns an attractive bronze-orange to orange-red.
The bark of the Okame cherry is particularly interesting in winter with the foliage absent. The pale rust-tan or gray, smooth bark has horizontal stripes of lenticels, or small spot holes, on it, and the satiny sheen of the bark reflects light.
The Okame cherry is well suited to USDA Winter Hardiness Zones 5 through 8. A chilly winter is required for the cherry to initiate flower buds the following spring. Plant 'Okame' in a full sun to partial shade exposure, so that it receives at least four to six hours of direct sunshine, the more sun the better for flowering and a uniform tree shape. In hot climates, consider placing this tree where it will receive shade in the hottest part of the summer afternoon.
Ideally, the soil for this cherry should be fertile and well-draining but moist. It demonstrates a good tolerance for sandy, loam and heavy clay soils and will handle drought at the expense of its foliage, which will dry and drop prematurely if the soil is too dry. Ensure soils are moist for the best performance of this tree perennially.
Placing a broad swath of organic mulch under the Okame cherry will benefit the plant, retaining soil moisture, deterring weeds and keeping soil temperatures moderated in all seasons.
The small mature size of the Okame cherry lends it to use in a wide array of garden applications, even in the smaller spaces common in most urban yards. Michael Dirr, noted plant expert of the University of Georgia, writes that this small tree is both stunning as a lone specimen and planted in small ornamental groves of three or five. It is a lovely tree to use to line an avenue. Planting this tree in front of a dark-colored structure or hedgerow of dark evergreens accentuates the pink flowering display.
Since this cherry flowers so early, its flowers and flower buds are susceptible to frost and freeze damage. Situating this tree in a location that remains cooler in winter may help delay the appearance of flowers, to avoid the encounter with awkward late frosts in February and March. However, a protected microclimate on the southwestern side of a building or evergreen grove can lead to even earlier flowering in mid- to late winter.