While pine trees can offer shade and privacy to your backyard, they present a challenge: few plants can grow in the soil underneath their canopy because the pines create shade and an acidic soil that many plants dislike. To enjoy your pine trees and also have flowering plants in your backyard, don't experiment--choose plants that grow reliably in that environment.
Lily of the Valley
Once established, lily of the valley (Convallaria majalis) can carpet the area under your pines with small fragrant blooms. The plants develop long, glossy green leaves and delicate bell-shaped white flowers that grow off a single stalk. Lily of the valley bloom in spring to summer. These flowers aren't particular about the type of soil they're planted in and enjoy an acidic environment.
Crested Wood Fern
Crested wood fern (Dryopteris cristata) grows well in full sun to full shade. This fern averages 1 to 3 feet in height and has dark green fronds. Ferns prefer a moist soil and lots of water, though the crestied wood fern can withstand dry conditions. It thrives in the acidic environment underneath pine trees.
Certain species of azalea (Rhododendron spp.) that are suited for part or full shade can thrive under pines. Azalea works well under established pine trees that are quite tall, since this flowering shrub can grow up to 20 feet tall. Gardeners can plant dwarf azalea that top out at 8 inches. Azalea bear trumpet-shaped flowers in hues or red, purple and white. The plants have waxy green leaves that are ovoid in shape.
Bleeding Heart (Dicentra) is a shade-loving perennial. The long stems bear heart-shaped flowers that give the plant its common name. Most commonly pink and white bi-colored, the bleeding heart's flowers also can be pure white, purple and white, or red and white. Bleeding Heart blooms in the summer and features fringed green foliage throughout the year.