Catalpa leaves refer to the leaves of Catalpa betulaceae distributed in Northeast China, North China, Central China, Southwest China and South China. Catalpa bungeana is one of the top ten famous trees in China, and it is also one of the important raw materials of Chinese medicine. Catalpa leaves also have certain medicinal value, which can clear away heat and toxic materials, reduce swelling and relieve pain, and are widely used in the preparation of traditional Chinese medicine. At the same time, sub-wood is also one of the commonly used materials in traditional furniture in China, which is often used to make mahogany furniture, screens, dining tables and so on.

Catalpa bungeana leaves have important application value in China traditional culture, and are used as the theme or main element of sacrifice and poetry. For example, Bai Juyi, a poet in the Tang Dynasty, used Ye Zi's "There is no good companion in the guest house at the gate, and the lonely wind is Meng Han" to describe the desolate scene; In Song Dynasty, Catalpa bungeana leaves were introduced into Guqin musical instrument, which was known as "five flavors" because it could carry forward the strong feelings of shepherd boys. In addition, traditional folk culture also uses catalpa bungeana leaves to make "catalpa bungeana pillow", which is said to help people sleep and keep fit.

Besides practical and cultural values, Catalpa bungeana leaves also contain profound cultural implications. Catalpa has a strong will and indomitable spirit, which can stand even in the storm. Therefore, it was called "resolute wood" in ancient times, and its leaves were endowed with spiritual symbols of strength, perseverance and perseverance. In traditional Chinese medicine, catalpa leaves have the function of relieving swelling and pain, and it is precisely because of its perseverance that it contains powerful power that it has such a curative effect. Therefore, catalpa leaf is also considered as a cultural symbol of strength and courage.