The gardenia is an attractive ornamental with attractive and fragrant blossoms that is often grown as a tree. But the gardenia is, in fact, a large shrub. And like most shrubs, it must be pruned periodically to clear away dead and damaged wood and to keep its size in check. Gardenias grown in the landscape are best left to take on their natural attractive shape and only need to be pruned once every two years or so. Gardenias grown in containers, however, must be pruned annually to maintain their size and shape. However often you prune your gardenia, wait until just after this season's blooms have faded to avoid sacrificing this or next season's blossoms.
Spray your pruning shears with disinfectant spray.
Prune away dead stems that have stopped producing new growth, broken stems and broken or dead branches back to their point of origin. Leave as little stump behind as possible.
Trim your gardenia to shape it or reduce its size. Prune any undesirable branches back a few inches until your gardenia takes on the size and shape that you desire. But be careful not to cut too much. Do not cut any branch shorter than four inches above the soil or it may not be able to grow back by next season.