I planted 4 "Shirotae" Mt Fuji ornamental cherry trees about 20 months ago when they were 6ft tall. The idea was to have them grow to a 15 ft height and train them to form an umbrella shape to cover a 30ft by 20 ft patio area. How do we begin to prune now that they are approximately 8-9ft high?
Leave them alone to assume parasol shape on their own. 8'-9' specimens have already been trained by the grower. Japanese cherries do not respond well to a lot of pruning, particularly cutting back. A canopy-like habit is typical of 'Shirotae'. Presumably this cultivar was selected or recommended because it would tend to develop as desired.
