pine straw /needles as mulch
I did a search to see if this was already discussed, but couldn't find it. So sorry in advance if it's already been covered!
Since my rose beds are expanding every year, it's getting more $$ to buy nice mulch and haul it all over my yard. We have a LOT of pine trees around here, and I noticed that Norfolk Botanical Gardens' Rose Gardens uses pine needles. I am assuming that is the same thing as pine "straw"?
I was thinking of using pine needles as mulch, but is there any danger of the soil becoming too acid over time? And every year, should I just throw a new layer of pine needles to the beds over the old stuff, or scrape off the old needles?