I've got some blueberries I started in large containers this year. I have not yet mulched them, but I'm already noticing that the top of the mix dries out fast. I'm actually going to move them where they get more sun, so....

I've read sawdust is great, but I don't have access to that. I have "medium western bark" leftover from making the blueberry container mix - would this be OK as a mulch? As you can imagine, they're medium sized bark chips.

Elsewhere in the yard, I tend to use hardwood fines as mulch. Would this be suitable for raspberries when I get around to planting them?