Spec's Garden - I am thinking of a complete change

I have quite a lot of soft green waste to be cleared from the garden, with French marigolds, dahlias, rudbeckias, asters and crocosmia (without the seedheads) I am thinking of running over all of it with the lawnmower to shred it up, then covering the veg bed with it, I have been mulching the garden with similar over the past year, grass cuttings, seedless weeds and thin branches from shrubs etc. but it has always been around established plants with no ill effects but can anyone see a problem with sowing seeds and transplants