Love love love pine needles. I have some Swiss stone pines that drop needles every fall. I take part of the drop each season and use them wherever I want to suppress weeds, and I put some around my hydrangeas. I just planted a rhodie last spring and I am putting the needles around that also. Whether acid or not, they are great mulch. I personally like the look, but you could put them under your other bark or whatever mulch if you don't like the appearance. These are absolutely the best weed suppressors I have ever found.
