Use lots of ferns and hostas.
You would need to find the plants you need that will live under a pine tree, not much lives under the canopy since it changes the soil. I am not sure how it is changed, but it is hard to get much to grow under them.
Hostas, azaleas, coral bells, ferns, plantain lilies, wild geraniums are plants that do well under pine trees. Mix these plants in, use mulch or let the pine straw be your mulch. Add a few rocks for visual appeal.
We haven't put anything under the Pondersa Pine tree....evidently soil has changed because nothing seems to grow....(except a few scraggly weeds which I have to trim).... farther on one side we have a bed of ferns, but under the tree nothing.