There are basically three main types of Hornbeams (Carpinus) used for Bonsai. The are:

Carpinus betulus – European Hornbeam

Carpinus caroliniana – American Hornbeam

Carpinus turczaninowii – Korean Hornbeam

All three make wonderful Bonsai trees. Some American Hornbeams turn brilliant red in the fall. Korean Hornbeams are easiest to find as pre-Bonsai or Bonsai trees in the USA.

Refining a slender Korean hornbeam by Jonas Dupuich  New 07-04-2021

Videos:

Bonsai Timelapse – American Hornbeam by Eisei-en Bonsai  New 10-25-2018

Deciduous Raft Design by Ryan Neil  New 03-09-2021

Korean Hornbeam by Mauro Stemberger  New 05-26-2020

“The naturalistic Bonsai style, by Walter Pall” by Bonsai Empire  New 06-19-2019

Spring growth on Beech, Hornbeam, Zelkovas etc by Peter Warren  New 05-17-2020

Working Deciduous – korean Hornbeam by Mauro Stemberger  New 03-09-2021