Hi Tim- Thanks for your question about the various mulches (they are all technically mulches) that you can put on your flower bed. They all have pluses and minuses so I'll include an article from Oregon State, but skip down to the part where it says "Choosing a mulch" to see what is available.

Since you already added compost, I would suggest getting a soil test if you want to use that as mulch, as the nutrients in compost can last awhile. If you are looking to control weeds and conserve water, you probably want bark or wood chips. I love arborist chips which can be had for free on chipdrop.com. They are rather big but don't need to be replaced often. You do have to have a sizeable area where they can be dumped, however.

Bark and wood chips can be bought at gardening stores and also last a long time. And if slugs are a problem for your flowers, I have had good luck with hazelnut shells, although they are expensive to put over a very large area.

Of course shredded leaves are also a good mulch if you have a tree that is dropping leaves at this time. They will decompose faster than wood products, but then the tree will supply you with a new batch next year!

https://catalog.extension.oregonstate.edu/ec1629/html

https://s3.wp.wsu.edu/uploads/sites/403/2015/03/wood-chips.pdf

Whatever you choose, mulching is a great way to help your plants stay weed free and well watered!