Oleander bushes are relatively easily to grow, though their pruning can be somewhat tricky. Oleander is an evergreen tree known for its copious blooms and ability to survive in most soils. Their flowers are quite the visual treat with widespread splashes of orange, yellow, red, and white blooms. Pruning oleander determines whether the plant grows as a shrub or as a tree. As a tree it can grow 10-18 feet tall while as a shrub it is much smaller.
If you simply want to grow your oleander in its natural form than little pruning is necessary. As a tree it can be grown with a single trunk or you can prune it to have more texture and depth with multi-stemmed bases. Whichever you choose, there is some pruning that must be done regardless. All pruning should be done in late summer to early spring as this will stimulate future branch growth and fuller blooms.
When your trunk begins to sprout new suckers on its base and on the ground surrounding the tree, you must cut them off. Suckers are efforts by the tree to grow new branches and they must be removed because they steal nutrients that the tree needs to grow properly.
If you wish to grow an oleander shrub than cut the stems closest to the ground. New stems will grow back with even more blooms. Also, make sure to trim the tops of your stems to maintain that bush-like appearance.
To have your oleander grow as a single trunk tree, you need to keep the strongest and straightest stem and remove the rest. Stake this stem when it’s young to support straight, upward growth.
To grow multi-stemmed trees, you should remove all the stems except for several strong, main stems. Then remove all the foliage from the lower two-thirds of your remaining stems. Tie together the tops of all your stems so that your blooms flow outward in an umbrella shape.