HI,I WAS CURIOUS IF IT WAS OK TO PRUNE MY HUGE ARBORVITAE HEDGE IN MID AUGUST?USUALLY I DO IT IN MARCH OR APRIL,BUT DID'NT HAVE TIME THIS SEASON.MY NEIGHBOR RECENTLY PRUNED HIS,AND WHERE HE MADE HIS CUTS THE TREE IS NOW BROWN,LIKE IT GOT BURNED IN THE VALLEY HEAT...
I agree with you. Wait. Sudden exposure to the sun as a result of major pruning at this time of year will shock the plant. It is not necessary. I recommend late winter, early spring hedging time.