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how to stop weeds from growing under pine trees

You can get in-depth information on drip irrigation from the Irrigation and Green Industry Network in the “Where to Find It” section.

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The frequency and timing of your fertilizing efforts are also crucial to healthy lawns. Both vary depending on your lawn type and the length of your growing season. Most northern lawns need only one or two applications of fertilizer annually—once in fall and sometimes a second time in spring. Southern grasses might require three feedings—early to mid-spring just after the grass greens up, early summer and again in early fall.

Apply Preemergence Herbicides

You can also use landscape fabrics to control weeds under decks and in pathways (spread over the excavated soil base before you add gravel or sand). A 3×50-ft. roll of landscape fabric, such as the Typar shown below, costs about $10. The fabric is also available in 36-in. die-cut circles (about $3 each) for installing at the base of trees.

This Preemergence herbicide, made from corn gluten, is nontoxic. You can safely use it near all of your vegetables as well as around ornamental plants. Photo by Saxon Holt

6 Weeding Mistakes

Any weeds that grow through mulch are easy to pull because the soil remains loose. Photo by Saxon Holt

Lee Valley Tools Ltd.
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Ogdensburg, NY 13669-6780
Telescoping Crack Weeder

How to stop weeds from growing under pine trees

An organic mulch, such as a mulch made from bark and fallen pine needles, works well to prevent weeds and return nutrients to the soil. Organic mulches may need to be reapplied about once per year, because they break down over time. Fabric mulches are a longer lasting option, and they can work for as long as 10 years. However, many gardeners find fabric mulches unattractive, and they also do not add nutrients to the soil like organic mulches do. The type of mulch to use around a pine tree is a matter of personal preference.

Plan on applying at least 3 inches of mulch to sufficiently prevent weeds. Apply the layer all around the base of the pine tree, but make sure to keep the mulch at least 6 to 12 inches away from the tree trunk. Mulches hold lots of moisture, and trees tend to have problems with diseases and insects when their trunks are consistently wet. Do not apply organic mulch over fabric mulch, because these mulches layered over each other can cause weeds to germinate.

Many gardeners dislike weeds growing around their pine trees. They make a yard look less cared for, and they can spread from the area beneath a pine tree to a nearby vegetable garden or landscape. Weeds also compete with trees for water and soil nutrients and can reduce the health and size of trees or other plants that they grow near. A combination of weeding and mulching is usually the best way to keep weeds from growing under pine trees. Herbicides are not recommended because some can harm pine trees can can be difficult to apply.


Cultivation is the practice of weeding and tilling around the base of trees to get rid of unwanted weeds. Although cultivation can theoretically be used as a primary weed prevention method, many gardeners do not want to spend enough time cultivating to get rid of weeds with this method alone. Therefore, it is a good idea to cultivate an area before planting pine trees and before applying mulch around the bases of the trees. Gardeners should simply use a hoe or shallow tiller to remove weeds when the soil is moist after irrigation or rainfall.

After removing weeds through cultivation, applying a layer of mulch works well to prevent more weeds from growing in the future. Mulch has an initial cost and takes some work to spread, but it does not require very much maintenance. Mulch also provides extra nutrients to the trees and helps the soil retain moisture.

Types of Mulch

Lisa Chinn developed her research skills while working at a research university library. She writes for numerous publications, specializing in gardening, home care, wellness, copywriting, style and travel. Chinn also designs marketing materials, holds a Bachelor of Science in psychology and is working toward a PhD in cognitive neuroscience.

How to stop weeds from growing under pine trees

Cultivate the soil underneath the pine trees about 8 to 10 inches deep with a tiller, hoe or spade, keeping a distance of about 6 to 12 inches from the trunk. Adjust the depth as necessary when you come across the rare shallow root.

Rake under the trees and set the pine needles aside to use as mulch. Wearing sturdy, garden gloves, discard the cones, trash and other debris. Pull any weeds, including their roots. Or, spray them until they are wet with a ready-to-use, non-toxic herbicide that specifically targets the problem weeds. You can also use a non-selective herbicide, but direct the spray on the weeds to ensure you do not get any other plants wet. Perform this task two weeks before landscaping under the trees so you can reapply the spray in one week’s time to kill any surviving weeds.

Step 3

Spread the saved pine needles around the plants; stay about 2 or 3 inches from woody stems and trunks. Add additional mulch, such as wood chips, to form a 3-inch layer of mulch, which is sufficient for weed prevention. As the pine needles fall, gently shake the plants and spread them around the garden to maintain the 3-inch layer. Using mostly pine needles as mulch rather than another type avoids the need to clean and remove the needles to get the desired look.

Select plants that tolerate shade and the acidic soil that is created by decaying pine needles. Also, select plants that are drought tolerant, because they will have to compete with the pine trees for water. Ground covers, shrubs, perennials and annuals can work well under pine trees. A well-designed area of a variety of plants might best fit your needs. Examples you might grow include: common yarrow (Achillea millefolium), hardy in USDA zones 3 through 9; and Snow of the Mountain (Aegopodium podagraria), hardy in USDA zones 4 through 9; and ostrich ferns (Matteuccia struthiopteris), hardy in USDA zones 3 through 7. Reminiscent of a redwood grove, ferns banking the base of the pine lend a forest feel, while the flowers add pops of color.

Step 2

Cut low-growing limbs to increase sunlight conditions and to gain more room for growing plants. Cut limbs flush to the trunk or to the branch unions from which they grow. Use a pruning saw or loppers, depending on the size of the limbs. Sterilize the tools with a disinfectant prior to use.