Question
My gardinia leaves are turning yellow and falling off.

Answer
Beth,

One of the biggest pests of gardenias is white fly. I would recommend checking the plant for tiny white flies. These insects suck the juices out of the leaves, causing them to yellow.

Aphids could also be a problem, as well as over watering, both of these can cause the same yellowing of the foliage.

Have the soil tested for it's Ph and organic matter. Gardenias prefer acidic soils that are high in organic matter.

Good luck,
Ed Gulliksen