Citrus sinensis 'Washington'
Common Name: navel orange 
Type: Broadleaf evergreen
Family: Rutaceae
Zone: 9 to 11
Height: 8.00 to 15.00 feet
Spread: 8.00 to 15.00 feet
Bloom Time: March to April
Bloom Description: White
Sun: Full sun
Water: Medium
Maintenance: Medium
Suggested Use: Flowering Tree
Flower: Fragrant
Leaf: Fragrant, Evergreen
Fruit: Showy, Edible

Culture

Best grown in deep, evenly moist, well-draining, slightly acidic, sandy loams in full sun. Intolerant of heavy, saturated soils. Hardiness varies based on the cultivar, but in general oranges can be grown in Zones 9-11. Care should be taken to protect young trees and new growth on mature trees in the spring if temperatures fall below 32°F. Can be grown in colder climates as a container plant and brought indoors during the winter.

'Washington' is known to have a somewhat narrow preferred climate range. They do not perform well in hot, semi-tropical environments, or in drier, desert conditions. Best grown in Zones 9-10.

Noteworthy Characteristics

Citrus sinensis, commonly known as orange or sweet orange, is a small evergreen tree originally domesticated in subtropical Asia. These plants can reach up to 30' tall. Slender spines may be found at the leaf axils, particularly on new growth. The glossy, aromatic leaves are ovate in shape and can reach up to 4" long. Their petioles are winged. Clusters of up to six fragrant, creamy white flowers bloom in early spring. The fruits are round to slightly oval in shape and can vary in size from 2-5" in diameter. The color of the fragrant, exterior rind varies from yellow to deep orange, and the sweet, interior pulp can also vary in color from a bright orange to orange-red.

Citrus sinensis is not a naturally occurring species. Based on genetic analysis, most experts agree that this is a hybrid plant resulting from a purposeful cross between a hybrid mandarin orange (Citrus reticulata) and and a hybrid pomelo (Citrus maxima). Exactly when and where this cross took place is not fully understood, although some evidence suggests southern China may be the point of origin.

The genus name Citrus is from classical Latin.

The specific epithet sinensis means "from China", and refers to the center of early domestication of this plant.

The common name orange entered the English language via the Old French orenge, a derivative of the Arabic name for this plant nāranj.

'Washington' is a navel orange cultivar characterized by its sweet, seedless fruit with an easy to peel rind that matures earlier in winter than other oranges. The fragrant, white blossoms emerge in spring. At maturity, these trees reach a medium size of up to 15' with a similar spread. They have well-branched, rounded canopies with slightly drooping branches. When grown in a container they will not reach their maximum size, but will still flower and set fruit well.

Problems

Susceptible to a number of insect pests including citrus rust mite, citrus snow scale, purple scale, Florida red scale, mealybugs, whiteflies, aphids, and fruit flies. There are also many diseases affecting oranges, including greasy spot, stem-end rot, sweet orange scab, citrus canker, and citrus greening disease.

Uses

Oranges are widely cultivated for their fruit and essential oil. Can be grown in a container. Also suitable as a small ornamental tree in the home landscape, Mediterranean garden, or edible garden.