Hello Marie,

Gardenias are evergreen shrubs.  Yellowing and dropping of older leaves (lower on the plant) are normal, especially in early spring and fall. If new leaves (on branch tips) become yellow (chlorotic), a deficiency of a micronutrient—usually iron—is often the cause. The primary problem causing the deficiency may be related to soil pH (the soil may not be acidic enough for gardenias).

Use a liquid fertilizer for "acid loving plants".  Read and follow directions on the package.

Make sure your container has drainage holes and that the decorative pot doesn't have water sitting in the bottom.

Linda Svoboda
Horticulture Program Educator
Cornell Cooperative Extension of Broome County
840 Upper Front Street Ste. 1
Binghamton, New York 13905-1566