Over fertilize?

[ghsgrad]

I have several gardenia bushes among other shrubs in my southern california garden.The other shrubs look healthy but the gardenia leaves are a pale green, darker green veins, brown edges. Soil pH was 8 so I added mulch,15-15-15 fertilizer and sulfur at different times. No improvement. Is the problem too much fertilizer? Suggestions?

[SusieQ]

Gardenia's need Magnezium ...for green up or food for acid loving plants, never heard of sulfur for them?

[Chris]

I imagine it was probably the PH as much as anything else, 8 is really alkaline, most plants won't like that.