Strelitzia are tropical plants which require high temps and high humidity. Chances are, the lack of humidity is causing the brown edges although it could be a lack of water.

Red spider mite will tend to make the plant go kind of marbled on the leaves...a daily or even twice daily good misting of the leaves with water...preferably rain water, especially the undersides, will help eradicate RSM and also help keep the plant humid.

Where are you keeping the plant ? is it behind glass...hot, dry and sunny ?

Thank you for your knowledge. The plant has been sitting on my decking in full sun. It has never dried out. I spray the leaves every day. I do believe it has spider mite and have taken a picture which I will send to you.

Thanks again

ShazziePx