|This article includes a list of references, but its sources remain unclear because it has insufficient inline citations. (November 2009)|
The shangjuan, or Ichang lemon (Citrus ichangensis × C. maxima), is a cold hardy citrus fruit and plant originating in East Asia. According to some it is the best bet for cold-hardy citrus with edible fruit. It is believed to be a hybrid of pomelo and Ichang papeda and thus may also be called Ichang pomelo.
Shangjuan forms a shrub or small tree, which is commonly thorny. Leaves are notable for a large petiole, resembling those of the related Kaffir lime and Ichang papeda, and are fragrant. The large fruit has a flavor resembling a mixture of lemon and grapefruit, and is occasionally used as a substitute for those fruits. Like other citrus fruit with C. ichangensis ancestry, the shangjuan is relatively cold-tolerant.
The fruit looks a bit like a grapefruit, and can be either pale yellow or green depending on the degree of ripeness. Shangjuan fruits, which are very aromatic, can be as large as a grapefruit (up to 10 cm or larger).