How to prune chestnut 'colossal'

Late winter while fully dormant — avoid pruning in autumn when wounds are slow to seal. Select scaffold branches with wide-angle crotches and remove narrow-angled or crossing competitors early. On mature trees make thinning cuts back to a lateral or the collar — avoid large stubs which invite disease. Remove water sprouts through summer if they are dense.

Annually during the first five formative years; every one to two years once established. Castanea 'Colossal' is a vigorous hybrid chestnut that needs formative pruning in its first five years to build a strong scaffold of four to six main limbs. Thereafter prune annually in winter to remove dead wood and thin crowded branches. Good canopy light improves nut size markedly on this cultivar.

Select scaffold branches with wide-angle crotches and remove narrow-angled or crossing competitors early. On mature trees make thinning cuts back to a lateral or the collar — avoid large stubs which invite disease. Remove water sprouts through summer if they are dense.