To propagate a Hornbeam tree, the most common method is by taking softwood cuttings in late spring or early summer, selecting healthy, non-flowering shoots, dipping the cut end in rooting hormone, and planting them in a well-draining potting mix with high humidity to encourage root development; alternatively, you can also propagate Hornbeam from seeds, though this method can be slower and requires a cold stratification period to achieve germination;. 

Key points about propagating Hornbeam:

Propagation method: Primarily through softwood cuttings, but seed propagation is also possible. 

Best time for cuttings: Late spring to early summer when new growth is pliable. 

Cutting preparation: Take 4-6 inch cuttings from healthy shoots, remove lower leaves, and dip the cut end in rooting hormone. 

Planting medium: Use a well-draining mix like peat moss and perlite. 

Creating humidity: Cover cuttings with a plastic bag or place in a propagator to maintain high humidity. 

Seed propagation: Requires cold stratification (keeping seeds in a cool environment for a period) to promote germination. 

Important considerations:

  • Professional propagation: While possible at home, propagating Hornbeam can be challenging for beginner gardeners, and some cultivars may be better left to nursery professionals.
  • Plant patent restrictions: Check if the specific Hornbeam cultivar you want to propagate is protected by a plant patent.
  • Root development time: Be patient, as rooting from cuttings can take several weeks.