Ask Mr. Smarty Plants

This is one of our most frequently asked questions: "Why won't anything grown under my (fill in the name of the tree)? If you really want to know what, if anything, will grow under your Pinus strobus (eastern white pine), take a walk in the woods where they grow naturally and see what is growiing under them there. That is probably not a very practical suggestion, so we will try to answer your question. There are several problems with understory plants growing under just about any tree, the first one being the shade of the tree itself. The pine, being evergreen, keeps the ground beneath it pretty well shaded year-round. So, that's Strike One. Strike Two is the issue of allelopathy, in which mature trees often emit substances to discourage the growth of competing plants beneath them The black walnut is the poster child of allelopathy, and other trees have the capability in lesser degrees. The pine is considered only moderately guilty of killing off the competition, but it still must be considered. Allelopathic substances can be in the twigs, foliage or roots; fruit, twigs or foliage cause significant litter beneath the trees, inhibiting just about anything from coming up. Strike Three, the Pinus strobus has a root system that is usually shallow and highly branched with many fine roots close to the surface of the soil, effectively preventing any other plants from getting a foothold or water and nutrition from the soil. The pine needs an acid soil, and helps to perpetuate such a soil from its foliage, which makes the soil acidic. 

Read this USDA Forest Service website Pinus strobus to find out other traits of your tree, including possible pests and diseases. We are going to try to find some plants that might be able to survive in that situation, but we wouldn't bet on any of them flourishing. In the end, you might have to decide-tree or decorative understory plants? We are going to go to our Recommended Species, select Michigan on the map, and search on herbaceous blooming plants and shrubs, looking for plants that like acidic soil, shade and are woodland understory plants. Follow each plant link to the webpage on that plant to get other information on it. We consider "part shade" to be 2 to 6 hours of sun daily, and "shade" to be less than 2 hours of sun daily. Please remember, we make no guarantees these plants will thrive, or maybe even survive under your white pines.

Herbaceous blooming plants

Arisaema triphyllum (Jack in the pulpit) - 1 to 3 ft., blooms green, purple, brown March to June, sun or shade

Asarum canadense (Canadian wildginger) - 4 to 8 inches high, blooms red, green, purple, brown April to June, part shade or shade

Athyrium filix-femina (common ladyfern) - 2 to 3 ft tall, part shade, shade

Chelone glabra (white turtlehead) - 1 to 4 ft. tall, blooms white, pink July to September, sun, part shade or shade

Mitchella repens (partridgeberry) - trailing evergreen, 2 inches high, blooms white, pink, purple May to October, part shade or shade

Sanguinaria canadensis (bloodroot) - to 1 ft. tall, blooms white March and April,, part shade, shade

Viola pedata (birdfoot violet) - 4 to 10 inches high, blooms blue, purple March to June, part shade, shade

Shrubs

Arctostaphylos uva-ursi (kinnikinnick) - trailing evergreen shrub, to 3 ft. tall, blooms white, pink March to June, sun, part shade or shade

Ceanothus americanus (New Jersey tea) - to 3 ft. tall, blooms white March, April, part shade or shade

Diervilla lonicera (northern bush honeysuckle) - to 3 ft. tall, blooms white March, April, part shade, shade

Hypericum prolificum (shrubby St. Johnswort) -to 3 ft. tall, blooms yellow June to August, part shade, shade

Actaea pachypoda

Arisaema triphyllum

Asarum canadense

Ipomoea imperati

Chelone glabra

Mitchella repens

Sanguinaria canadensis

Viola pedata

Arctostaphylos uva-ursi

Ceanothus americanus

Diervilla lonicera

Hypericum prolificum