Pine Needle Mulch

Pine Needle Mulch

Im in zone 6, Colorado with a fully xeriscaped lawn. My summer project is rebuilding my beds as the latest doggy addition to my household has taken to digging in them. Once I build up some walls and add some much needed soil, I will need to mulch the beds. Would pine needle mulch work in my case? I like the look of it but am afraid of the acidity.
Purple Jumanji flower??!!

Purple Jumanji flower??!!

update

update

Mushrooms

Mushrooms

Ugh, help me!!

Ugh, help me!!

Resident bird

Resident bird

Oh, the frustration!

Oh, the frustration!