I apologize for this delayed reply to your gardening question and hope it is still helpful to you.
Either would be fine. The palms would do well with either mulch choice. If the grass is bermuda or another perennial grass it should be removed or sprayed first otherwise the landscape fabric should do the trick.
Thanks for the question. Best wishes for a wonderful gardening year in 2007. Please stop in again soon!
Q&A Library Searching Tips