Remove the gardenia from its pot carefully. Crack the pot to dig around the root system, if necessary.
Choose a relatively open space in your garden soil. Plant the gardenia in the uncrowded soil. Ensure that the root ball is an inch higher than the soil.
Trim up to 1/2 of the gardenia's top growth to prevent wilting through water stress.
Surround the transplanted gardenia with mulch to stop weeds from competing with the gardenia's roots. Pull weeds out by hand if you notice them.