Need help with my girl. (pics)

I this is one of my plants, this is the problem as you can see on the pic there is like a big brown stain. this plant is getting rain water and is outdoor. any help please!

Ae you liveing in the city this can sometime's cause burns on the leaves i guess it is from all the shit that populated areas pump up into the air and it all comes back down in rain.collect a small sample of rain water and do a ph test on it i bet the rain water is acidik.or the soil may be acidy add a little lime just a tad around the plant and hen wash this in you may need to have some on stand by for future use.take off all of the bottom leaves lollypop it the root system will learn to deal with the problem that is why it is best to keep the leaves away from the soil.

Any other help!!

You can always collect a sample of the rain water and take it in for analysis and see what is in it. Try adding some vitamin b1. That helps plants that are stressed and helps the plant rebalance itself.