Tender toona sinensis is a nutritious seasonal ingredient in Chinese cuisine. [Photo/sipaphoto.com]

The traditional Chinese lunar calendar divides the year into 24 solar terms. Grain Rain (Chinese: 谷雨), as the last term in spring, originates from the old saying, "Rain brings up the growth of hundreds of grains".

It signals the end of cold weather and a rapid rise in temperature. In southern China, people drink tea on the day of Grain Rain to nourish the body, while in northern China, another tradition is to eat toona sinensis, tender tree leaves that serves as a vegetable in the spring.

"Toona sinensis before the rain is as tender as silk," the old saying goes. The flavor is garlicky, earthy and bitter. In traditional Chinese cooking, people would chop up the leaves, and fold them into scrambled eggs or make toona sinensis fritters.

Tender toona sinensis is a nutritious seasonal ingredient in Chinese cuisine. [Photo/sipaphoto.com]

Scrambled eggs with chopped toona sinensis and carrot [Photo/sipaphoto.com]

Freshly baked toona sinensis fritters [Photo/sipaphoto.com]

Toona sinensis and tofu salad [Photo/sipaphoto.com]

Blanched toona sinensis [Photo/sipaphoto.com]

Tender toona sinensis leaves grow on a tree during the spring. [Photo/sipaphoto.com]

Tender toona sinensis leaves grow on a tree during the spring. [Photo/sipaphoto.com]