Ask Mr. Smarty Plants

Anytime there is a slope or the potential of soil erosion, think first of grasses. Their thick, fibrous root systems tend to hold soil in place. This is a common problem so you may want to peruse previous answers from Mr. Smarty Plants such as this one, which sounds similar to your situation. While some trees are allelopaths, destroying grasses around their bases, the pines do not have this characteristic. In searching for grasses specific for your site, think tall so the grass isn't buried under the pine mulch. To that end, all of the following suggestions range between 2 1/2 and 8 feet tall and will thrive in a part-shade environment. You may need to remove some of the pine needles when getting the grass started. Take a look at our article on Meadow Gardening for seeding advice. Grasses can be mixed with tall flowering native plants to add color.

Elymus hystrix var. hystrix (eastern bottlebrush grass)

Melica nitens (threeflower melicgrass)

Panicum virgatum (switchgrass)

Sorghastrum nutans (Indiangrass)

Tridens flavus (purpletop tridens)

Depending on how steep the grade of the slope, you may want to consider another idea even though the plant is lower growing. Pine needles produce an acid soil environment. In some parts of the United States, pine needles are baled and sold for mulch. Acid soil + natural acid mulch = blueberries! The roots of blueberry shrubs are shallow, fibrous, thick, and prefer sandy soil. Along with some grass to help get them started, they may do the trick especially if you are able to terrace the slope a bit. If you don't want the berries, the birds will.

Vaccinium corymbosum (highbush blueberry) is the native plant from which commercial blueberry cultivars are derived. They may well be growing wild in local Wisconsin conifer forests.

Use our site to find a list of suppliers in your area or use this EPA list for Wisconsin. 

Elymus hystrix var. hystrix

Melica nitens

Panicum virgatum

Sorghastrum nutans

Tridens flavus

Vaccinium corymbosum