Introduced into North America late in the 1800's for ornamental plantings, erosion control and wildlife habitat improvement, Russian olive proved invasive and impossible to control. Cut back to the ground, the tree sprouts multiple vigorous trunks. The natural multi-stemmed form creates dense thorny thickets and hedges. Careful annual pruning of established Russian olives creates a graceful shade tree similar to the true olive in appearance. Planting new Russian olives is now discouraged.
Select one stem to be the plant's leader and cut all others back to the ground with either limb loppers or a pruning saw. While the tree is small select limbs with rounded saddles--the connection to the main trunk--as major branches. Limbs with V-shaped saddles break easily and should be culled. Remove unwanted limbs by lopping or sawing to within a half inch of the junction with the trunk.
Remove branches growing below head height when at least two thirds of the canopy grows above that level. Thin lower limbs to correct drooping branches. Lifting the thorny canopy makes room for mowing and trimming around the tree.
Prune out broken limbs in late winter with a pole saw or pruning hook. Remove weak limbs or crowded growth to lessen the chances of limb damage in storms or from heavy loads of fruit.
Correct drooping branches by cutting back every other side branch on the main limb to a half inch from the branch collar--the ridge of tissue at the branch junction. Russian olive suffers few diseases and summer pruning to relieve the weight of heavy fruit crops poses little risk to the tree.
Cut back any sucker growth on the main trunk or from the tree's roots as soon as it's spotted. Mowing the area beneath the tree regularly prevents the plant from spreading.