When planting beneath pine trees, there are two major challenges: The dense distribution of branches and needles makes it very difficult for light to get through to plants below---and the ground beneath a pine tree becomes acidic from the constant falling of pine needles. There isn't much that you can do to prevent these problems, but there are a few plants that can thrive under these conditions.
Growing on vines that spread out across the ground, wild strawberries can grow quite well in shaded areas and don't mind the acidity of the soil under pine trees. Pine needles can serve in the place of straw and keep the strawberries out of the dirt so that they are ready to be picked. If you want to actually eat the berries though, you must be vigilant, as the same birds that are attracted to the pine trees will eat the strawberries beneath as quickly as they ripen.
Azaleas and rhododendrons are two popular types of flowers that grow well in the shade of a pine tree and do well in acidic soil. In fact, azaleas and rhododendrons grow so well under acidic conditions that the pine needles that fall around them can be left as mulch. Geraniums can also survive with very little sun in the acidic soil beneath pines.
Shrubs and Vines
There are a variety of popular shrubs and vines that can thrive without a great deal of sunlight in the acidic soil under pine trees. Ivy, Periwinkle, Hostas, Sweet Woodruff and Silver Nettle are all known to flourish in the shadow of towering pines. Lily of the Valley also grows well in the shade and acidic ground.
Despite the lack of light, shrubs and vines can be expected to stay green all summer and blossom with their small flowers and fruits throughout the blooming period.
Help Plants Thrive
To ensure that the flowers and shrubs you plant beneath your pine trees do well, you may want to give them extra care. Organic fertilizer and mulch help provide nutrients to your plants to endure the tough growing conditions beneath a pine tree.