I've read that the soil under an evergreen will be slightly more acidic due to the needles falling, but not as much as people believe.

To me, the bigger problem is that it's dry and shady under the tree and the tree readily uses up any nutrients and water that you provide. I've tried that nightmare of a ground cover, goutweed, and even that barely did anything. The ground under my spruce consists mostly of dried needles and bare ground, not even very many weeds grow.

Still, who knows? By applying a bit of new soil, or watering well, you might have success, I'm just telling of my experience.

Thanks for the reply glen3a.
I have cleared away most of the pine needles and I am able to dig down a fair way in some places without hitting the large roots and have found the soil quite sandy. I think I shall give some heathers a try next year after adding some ericaceous soil to the plot. I have monitored the sun and it seems that this area under the tree gets quite a bit. I shall also monitor the rain as soon as we get some to see how the ground hold the moisture now that it is open to the elements.

Thanks again,
Brian