Carpinus caroliniana "Cultivation Notes"

Carpinus caroliniana /American hornbeam
Bonsai cultivation notes

Position Carolina Hornbeams prefer slight shade particularly from mid-day sun, provide wind and frost protection in winter.  They have a tendency to lose lower branches when exposed to extreme elements.

Feeding Feed every week with a well balance fertilizer for a month upon leaf break in spring, every two weeks thereafter.  Stop feeding when the day time temperatures exceed 93 degrees F.  Late summer and early fall feed every two weeks with a low nitrogen fertilizer to stimulate and enhance bud and root growth.  Stop feeding 2-3 weeks prior to the first frost.

Watering Water generously throughout the growing season, hornbeams tend to dry out more quickly than other species (check daily).  Keep moist and well drained.

Re-potting re-pot in spring (before buds extend) every two years, when tree is ten years old re-pot as necessary when roots fill the pot. Hornbeams have a tendency to have a small number of straight, vigorous roots that emerge at angles from the trunk base. These need to be pruned back hard to encourage more numerous branching roots.
 
Pruning Allow the initial spring flush of growth to fully extend and harden off and then prune back the new growth very hard. This hard pruning will encourage back budding and a second flush of shorter, more compact growth for the remainder of the year while ensuring the tree remains vigorous. Remove large leaves as and when necessary.
 
Collected Specimens & Pre-Bonsai Collect specimens in spring before bud brake.  When collecting preserve the root system 8 inches from the trunk for every inch of trunk diameter.  Remove the original soil immediately keeping the roots moist and being careful not to damage the fine feeder roots.  Trim off the tap root and any large roots perpendicular to the trunk and seal with cut paste.  Cut the trunk two inches above where you want the new leader to grow.  Trunk cut Carolina hornbeams almost always bud out 1 to 2 inches below the cut; expect a few inches of die back.  Plant them directly into a well draining soil and water thoroughly with Super Thrive.  Place newly collected specimens in a shaded area until new buds have developed and extended.  Grow for one year without pruning allowing the root system to fully recover.  Before bud brake in the second year prune back the upper branches to one or two buds and let the leader in place to fully develop and build taper.  In the third and fourth years prune as needed to develop taper and anatomically correct ramification.  Prune leaving at least one bud, they will experience die back if there is no visible bud on the branch.  Seal all exposed areas with cut paste.

Defoliation Defoliate refined specimens in midsummer by removing all leaves leaving just one at the tip of each branch.  Defoliation is conducted on vigorous and anatomically mature specimens only, with the goal of reducing leaf size and promoting back budding.  This is stressful on the tree so implement every other year allowing a one year rest period.
 
Pests and diseases Coral spot, caterpillars and aphids, sun scorch to leaves.  Note: be sure to examine newly collected root systems for grubs.  Warning: Examine the root systems of collected specimens; I have noticed at least 1 in 4 contain a grub that bores into the base eating away at the feeder roots.