If you're looking for a bonsai tree with naturally small leaves, look no further than Carpinus turczaninovii - commonly known as Korean hornbeam. This species is lauded by experts as one of the best for bonsai, thanks to its petite foliage and flexible nature. Native to central China, the Korean Peninsula and central and southern Japan, this plant is a large shrub or small tree that can grow up to 20 ft tall and is hardy to USDA zone 5b. It can be easily purchased from commercial suppliers and can withstand hard pruning. The leaves of this tree are ovate, broadly ovate, ovate-elliptic or ovate-rhombic in shape, measuring between 2-6 cm long and 1.3-4 cm wide. They are hairy in some parts and have a serrate margin. The female inflorescence is 3-6 cm long with pubescent bracts that have five prominent reticulate veins. The nutlets are broadly ovoid and are about 3 mm long and 2 mm wide, resinous glandular and have prominent ribs. The Carpinus turczaninovii f. coreana is a somewhat disputed name which some say is a synonym of Carpinus turczaninovii. Others claim that they are different altogether. Ultimately, it's best to grow both and observe the difference for yourself. Bonsai enthusiasts love the Carpinus turczaninovii for its petite size and adaptability, and you will too!