Good morning and thank you for your question.  It is very difficult to determine if what is affecting your plants is a fungal pathogen.  Many plants will turn brown or black simply because their time is up.  It could be overwatering, or something else completely.  I would encourage you to try out your new locations for plants next year and see what happens. There are multiple pathogens that could infect the plants you listed and just one fungicide applications will unfortunately not do the trick.  It depends on which pathogens (could also be bacterial or viral) you are dealing with and the stage of the lifecycle in which it is it.  

If you start to see similar symptomology next year, I'd encourage you to send in samples to the plant an pest diagnostic clinic at OSU where they can closely examine what is going on and let you know if it is pathenogenic or environmental.  Here is the website for more information:  https://ppdc.osu.edu/home