Zone 5B if that matters
I have a wildflower garden that is 1 year old. It is a mixture of bulbs, perennials and annuals (that I hope reseed). I plan on adding more seed in the next week, especially in the bare spots and after that it is survival of the fittest meaning that hardier plants that survive year after year stay and those that don’t return … oh well. I need to mulch the garden to keep out weeds (yes I recognize that this runs against the idea of annuals reseeding but oh well) and retain water so want to know what is the best mulch for this type of garden? I’m assuming there is debate on this so that is why this is in GD and not FQ. Decorative mulch i.e. “lookin’ pretty” is not a concern in this section of my garden; I prefer the most functional mulch for my needs…
I use the cheapest garden dirt I can find in the 20lb bags. I find I get a lot less weeds with the “cheap stuff” that has no brand name, than if I choose Miracle Gro or Scott’s etc.
Also, I’ve had good luck with pansies and violas coming back and seeding themselves, even though they’re annuals. They don’t all come back, but I usually get quite a few wild ones. Good luck!
My violas may take over the world.
Moving this to IMHO since your are looking for advice.
As you probably realize, mulch sufficient to keep down weeds is also enough to greatly restrict reseeding of desired plants.
My preferred mulch for gardening in general is some type of feeder mulch. That includes small caliber/shredded bark, shredded leaves and mostly broken-down compost, which are eventually incorporated into and improve tilth of/enrich soil.