Olive, known botanically as Olea europaea, is a subtropical and evergreen plant that grows in a large shrub or small tree form. Established fruiting and ornamental olive trees do not require regular pruning for fruiting and their natural canopy form is fairly attractive. When the trees do need to be trimmed for size, clearance or aesthetic shape such as with hedging, they can readily tolerate it, according to Texas A&M University.
Prune your olive trees in the spring and summer only to prevent triggering new growth that may not have time to harden off before winter.
Trim away any dead, diseased, crossing, abrading or other problem wood and foliage throughout the olive tree canopy if needed. Place the cuts down to the point of healthy tissue or all the way down to the parent branch, just outside the branch collar.
Reduce the size of the olive tree canopy by trimming off the tips of the branches to the desired length. Work around the tree to distribute the cuts evenly and preserve the natural shape of the canopy as much as possible. Remove no more than 1/3 of the plant mass in any pruning session lest you risk a shock response in the tree.
Create long planes of flat or curving hedges by trimming your olive shrubs with long-blade scissor or motorized shears. Hold the blades roughly parallel with the plant and make consistent level cuts all the way around and over the top of the olive tree. Be sure to collect all of the clipping that fall into the plant and down to the soil to prevent disease conditions.