Monday, July 19, 2010

Orixa japonica

The one and only member of the Orixa genus ( tribe ) of plants, part of the Citrus family. It forms a moderate growing, dense, wide-spreading, deciduous shrub to 7 feet or more, that is native to mountainous parts of China, Korea and Japan. Some records include: fastest recorded growth rate - 3 feet; largest on record - 10 x 13 feet. Excellent for use as a natural unsheared hedge.
The alternately arranged, smooth-edged, ovate to obovate leaves are up to 6 x 3 inches in size. The attractive foliage is glossy deep green above, pale green beneath; turning to pale yellow during autumn.
The male and female flowers are both borne on the same plant at the same time as the emerging foliage. The male flowers are borne in small panicles up to 1.3 inches in length and the female flowers are borne singly. The flowers are borne on the previous years wood.
The brown fruits are 4 lobed and up to 0.7 inches in width.
The bark is dark gray.
Hardy zones 5 to 8; the Orixa thrives in Toronto and also in the hot humid summers found in the U.S. Mid Atlantic. It should be expected to thrive in most of the eastern U.S.
Orixa prefers fertile, light, acidic, well drained soil in sun or partial shade. It is tolerant of drought. No major pruning other than a light prune to shape in February or March is needed; however it is used as a hedge plant in Japan.
Propagation can either be from cuttings taken in summer or from seed planted in spring.

* photos taken on July 17 2010 @ Morris Arboretum, Philly, PA

'Pearl Frost'
Similar but improved form of 'Variegata'. The foliage is boldly-margined white and is very scorch resistant.

'Summer Sunshine'
Foliage is bright yellow at first, later turning to bright green.

Foliage is boldly margined in creamy-white when young.

* photo taken on June 23 2013 @ U.S. National Arboretum, DC

* photos taken on Sep 3 2017 @ U.S. National Arboretum, D.C.

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