QuestionsHow to growTrees and ShrubsPruningwhen to prune pyracantha 0 Vote Up Vote Down john shields asked 15 years ago i have 2 large spreads of pyracantha firethorn now in white blossom. i want to prune it in hard so as to make it grow horizontally but not at the expense of the season’s berries. when should i prune? 1 Answers 0 Vote Up Vote Down Gerry Daly Staff answered 6 years ago Pyracantha can be pruned in July, taking away the young whippy shoots that have not flowered as they are this year’s growth.