You can overfertilize any plant, really, but plumerias are heavy feeders. Personally, I'd try both at half the label dose and see how that goes, then add more or less depending on results. You need a good amount of potassium in a flowering plant fertilizer, nitrogen leads to leaves but no flowers. Do you know the analysis? It's the three numbers on the front. If you post that I can tell you what I think.

Think about the application method for each of these. FP is liquid and fast availability to the plant and Excal is granular very slow release availability. I think you could try it by adjusting dosage downward on both as suggested above and review results.

I would actually try a 3/4 excal and 1/4 dose FP to start. Reasons being Excal is less expensive and specifically engineered to Plumerias... per their own literature...but many of us know or have positive experiences with Tex, Kay, and formerly Carol and Luc. so are pretty comfortable with their assertions.

Thanks very much for your responses to my question. I'm glad I asked.

Hi Bill!!

As the others have mentioned, yes you can over fertilize and I would be careful with adding both at the same time. I will reduce the FP in the spring ( fall) or even if I give a little during the winter and I'll apply it at full strength during the peak summer growing season every two weeks or monthly.

My excaliber is applied only onetime since it's a 6 month time release when I bring out my trees in the spring and I'll let them get acclimated and watered well before I apply.. My trees still have some visible excaliber so I might reduce it like k has mentioned above.

Laura

Laura would you contact me, I have a proposition too offer someone of this forum. Thanks