PRUNING... Heavy pruning should be done in winter. Hornbeams are apically strong, meaning the apex grows faster then the lower branches. Occasionally you will need to radically prune the top while pruning less from the lower branches. In Spring after leaves have hardened off prune back to first pair of leaves on new shoots. Keep growth tips pinched off to encourage short internodes.
TRAINING... Wire can be used on main branches and some secondary branches, with itís short internodes, clip and grow is best for fine branching. Buds back well on old wood.
WATERING... Likes it in the summer especially, does not like to get dry. A little more organic matter in your soil mix will help.
LIGHT... Full sun. In a shallow pot or on a slab best keep from the hot afternoon sun.
INSECT/DISEASE... Aphids, especially with late spring/early summer growth burst. Check for ants crawling up your stems and black on top of your leaves for evidence of Aphids, soapy water will take care of them. Aphids are asexual so repeated doses on a 7-10 interval may be needed. Repeated summer afternoon rains can sometimes cause fungal leaf spots, although a little unsightly not a real harm to the tree.
REPOT... In winter when tree is dormant. January and February. Young trees will need repotted every two years while older trees may go three to four years.
FERTILIZE... A balanced 20-20-20 throughout the growing season.
SEASONAL... Cold hardy, needs to be left outside through the winter.
Species suitable for bonsai:
American Hornbeam Carpinus caroliniana
Korean Hornbeam Carpinus turczaninowii
European Hornbeam Carpinus betulus