how to fertilized mulched beds

My flower beds used to be mulched with crushed pine bark so every Feb i'd throw a little 13-13-13 and rake it in a little and water in

last year had beds redone and they put down 2 layers of weed fabric and mulched with 3-4 inches pine straw...it's worked great for weeds but I'm now wondering about fertilizer

can I just throw a little 13-13-13 on top of pine straw and let the rain soak it in, or do I have to remove the straw and weed fabric (not a trivial task) and get down to the dirt?

i have azaleas, sasanqua, foxtail fern, yewtopias, lorapetalum