Pines are difficult to grow grass under, so your best bet would be to go with the ground cover of some sort. Some ideas are packysandra, which may not thrive, but I have seen it do ok. Other low, cover types would be some of the contoneasters or maybe even some euonymus's (fortunei).<p>Now some other ideas would be this. You said it was a pine, so how big and how high up are the bottom braches?<p>If the tree is bigger, you may get away with some larger materials. I personally like Hydrangea's (NIKKO BLUE), as they like the acid soil and tolerate the shade. Other choices could be barberrys (c. pygmy for lower ht, rosy glow for higher), Hollys (helleri for lower ht), myrica (Bayberry), and redstem dogwoods (cornus alba)<p>Some other quick ideas would be to plant around the outside of the tree with larger material, and kind of hide the bottom area. Maybe layer some low growing annuals/perennails first, then work back with larger materials, having the pine towering over the back. Also, I've seen people build makeshift fences to help finish the effect of hiding the bottom of the pine when it bares out over time. Would work good especcially if the tree is in the background of the yard.<p>Finally, maybe just mulching the area around the tree and planting annual color during the season may be a option also, though the big pine usually dwarfs the little flowers and leaves it unproportional.<br>