Gardenias are tropical plants with large, white, fragrant flowers. They are extremely popular in the Southern United States, as they thrive in humid environments. Gardenia flowers have very precise care instructions. If these requirements aren't met and maintained, the plants will not bloom at all.
 Place gardenia flowers in an area where they will receive lots of bright light. Avoid direct sunlight in hot summer afternoons, but expose them to full light at all other times. If the plant is indoors, use a supplemental growth light to ensure your gardenia flowers get the light they need.
 Keep the soil around gardenia flowers evenly moist. Water them with room temperature distilled water. Gardenias are sensitive to the temperature of the water, so make sure it isn't too hot or cold.

 Keep the temperature around gardenia flowers above 60 degrees F and below 70 degrees F if you want them to bloom. Aim for an optimal temperature of between 65 and 70 degrees F during the day and between 60 and 62 degrees F during the night.
 Place gardenia flowers in the most humid area possible. They require very high humidity to bloom to their fullest. If the plant is growing indoors, use a humidity tray or a humidifier. Mist indoor and outdoor plants with a spray bottle filled with water at least once per day.

Feed gardenia flowers with an acidic fertilizer once every three weeks during the spring and summer. Fertilize once every six weeks during the non-growing season (fall and winter). Prune gardenia flowers while they are dormant, or after they have stopped blooming (usually in the fall and winter). Leave some leaves on the plant so that they will continue to produce food for the roots. Mulch gardenia flowers that are grown outdoors with at least 2 inches of mulch. Wood chips, bark, or sawdust works well for mulching gardenias. This will help keep the soil free of weeds, moist and cool.