Grass doesn't like to grow under pine trees for several reasons: 1) the soil is acidic, 2) there is little sunlight, 3) the competition for water is intense, and 4) pine needles fall straight down, creating a heavy blanket that further limits sunlight getting to the grass. For these reasons, many landscaping pros discourage planting grass at all under pine trees (offering the usual alternatives). But if you insist on making a go with grass under a pine tree, there are some things you can try. There are also some other plants that might work, depending on your situation (and your luck).
Growing Grass Under Pine Trees
Getting grass to grow under a pine tree requires dealing with the four problems mentioned above: acidic soil, little water and sunlight, and pine needles. Follow these tips to increase your chances of success:
- Clean the area of needles and debris to expose the soil (and any grass that's there) to sunlight and moisture
- Till the soil, preferably to a depth of 6 inches; however, dig only as deeply as the tree roots allow; do not damage the roots; for the same reason, it's best to dig by hand and not with a large rototiller
- Test the soil and apply lime, as needed, to decrease the acidity (raise the pH) of the soil; most grasses do best with a pH of 5.5 to 6.5
- Remove all tree limbs below 10 feet; prune or thin upper limbs, as practical, to increase available sunlight
- Use fescue seed for its shade tolerance; in the southern zone, you can also try zoysia, Bermuda and centipede grasses
Growing grass under pine trees is no easy task and will require constant attention. You will likely need to apply lime more than once, and it can take 1 to 2 years to have the desired effect of balancing the pH of the soil. It's also important to keep the area free of pine needles, as dead needles are what make the soil acidic, in additional to blocking sunlight. Plan on additional watering to compensate for competition from tree roots.
Growing Other Plants Under Pine Trees
Some plants are tolerant of the unfriendly conditions under pine trees, meaning they can handle shade and acidic soil. For best results, amend the soil with lime a year before planting to balance the pH. Start with small plants to minimize root damage when digging holes. Be sure to space the plants appropriately for their size at maturity. Plants that do well under pine trees include:
- Wild geranium
- Jacob's Ladder
- Ferns (Royal, Maidenhair, Oak, Lady)
- Sweet Woodruff
- Ivory sedge
- Woodland Sunflower
- Lily of the Valley
If you've thrown up your hands and given up the idea of planting anything under a pine tree, your best option is probably mulch. Or, you can simply encircle the no-growth-zone with an edging material and let the pine straw serve as your mulch. Extend the bed to the drip line of the tree to minimize yard cleanup. Landscape rock works fine, too, but it doesn't blend with the pine needles as well as mulch does, so you'll have to rake them up more often.