Celtuce (Lactuca sativa var. augustana, angustata, or asparagina), also called stem lettuce, celery lettuce, asparagus lettuce, or Chinese lettuce, IPA (UK,US) /ˈsɛlt.əs/. It is a cultivar of lettuce grown primarily for its thick stem, or its leaves. It is used as a vegetable, and is especially popular in Taiwan, and China, where it is called wosun, (Chinese: 莴笋; pinyin: wōsǔn), or woju (Chinese: 莴苣; pinyin: wōjù) (although the latter name may also be used to mean lettuce in general). In the south of China, it is also called (Chinese: 油麦菜; pinyin: yóu mài cài) or ‘ou sen’.
The pale green leaves, which are tender, and white stems, can be eaten raw (in salads) or cooked. It can be pickled, grilled, roasted, or stir-fried. It is mild but nutty, with a slight smoky aftertaste. It is high in vitamins.
It is thought to have come from the Mediterranean region and then brought to China during Tang Dynasty, about A.D. 600-900.
It can be grown from seed, sown from April and May. Into a set bed or a temporary nursery bed and then transplanted to the growing site. They should be spread 30cm apart each way. The young (edible) leaves are ready about 4-5 weeks after planting and the edible stems are ready when about 30cm tall, they are usually harvested between July and September.
The plant can suffer from aphid attack.
The stem is usually harvested at a length of around 15–20 cm and a diameter of around 3–4 cm. It is crisp, moist, and mildly flavored, and typically prepared by slicing and then stir frying with more strongly flavored ingredients.