Aug 16, Gaétan Paquet, an ecological arborist with 30 years’ experience pruning arborvitae hedges, recommends late summer pruning, from August 15 th to 30 th. By pruning at this time, at the tail end of the hedge’s growing season, the hedge will retain a dense, very conical shape through the winter that will prevent the snow from clinging to the twigs and prevent any. Dec 10, Active growth begins in spring and continues until dormancy in fall. Like most evergreens, arborvitae should be trimmed while it is dormant.
This is roughly from about Thanksgiving to St. Patrick.
Pruning Arborvitae to Shorten a Tall Hedge. Late spring after flowering - After the arborvitae has flowered and before mid summer is the best time to prune back a tall hedge row. The plant can maintain itself after flowering and maintain the height you are looking for. Dec 26, End of March through mid-April is an ideal time because arborvitae will quickly fill in and look good again after the chopping when you time it Estimated Reading Time: 2 mins.
Oct 02, Prune arborvitae to reduce height in the late winter, before the sap rises in the main trunk. To thin out overgrowth, prune in mid-summer, so new growth can take hold before the tree goes dormant for winter.
Prune down to ground. Dec 15, Because arborvitaes grow continuously during the growing season, you can prune them at any time through mid-summer.