Hybrid poplars are rapid-growing trees that many people plant in a landscape to provide fast shade. When you are growing hybrid poplars as shade trees, you must prune them to facilitate a canopy that will be healthy and provide effective shade. Regular pruning is important while hybrid poplars are growing during the growing season because branches grow so quickly on these trees. If you do not prune regularly, you may find the branches become so large and thick that they are difficult to remove. The biggest pruning job with a hybrid poplar is removing the suckers to control the growth. Other than sucker removal, pruning is generally unnecessary.
Begin pruning along the center trunk at the point where you want the canopy top begin. This is typically at the 8- to 10-foot point of the tree. Beneath this point, begin removing suckers that start to grow out from the center trunk by cutting them off at the trunk at a right angle to the sucker. It is best to remove these suckers while they are less than 3 inches long. Use either the lopper pruners or the pruning shears to cut off the suckers.
Continue to remove suckers to control the canopy growth during the growing season.
Prune older trees during the autumn or winter while they are dormant. Find limbs and branches that you did not prune during the growing season that are crowding each other, rubbing against each other or that look damaged. Remove these branches with the pole saw or the lopper pruners.
Watch for suckers to appear up to 30 feet away from a hybrid poplar. This is how groves of poplar trees form. If you do not wish to start a poplar grove, remove these suckers as they appear.