In a previous issue of Michigan Gardener, mint marigold was mentioned as being able to destroy bindweed and ground ivy. How do I grow it? Is there a better way to get rid of the ground ivy that is overrunning my lawn, garden, driveway, pond, and vegetable patch?

Mint marigold (Tagetes minuta) is a South American herb that grows readily from seed sown directly into the soil once danger of frost is past. It thrives in full sun and will choke out ground elder, bindweed, couch grass and ground ivy as it reaches its full height of six to eight feet. Considered a cash crop in South America for its oil, uses as a condiment and in beverages, it is sometimes considered a weed by others.

If bindweed is a problem in a large sunny area for you, it might be worth a try. However, ground ivy tends to like moist, shady areas as well as sun. For perennial weeds such as these two, there are three types of control: cultural (including crop rotation, such as growing the mint marigold), mechanical and chemical.

As was described in the “Weed Watch” column in the April 2004 Michigan Gardener, to naturally control ground ivy in turf grass, maintain turf density and health through proper culture. Mechanical removal in turf is difficult and rarely effective. Ground ivy is shallow-rooted and it roots at each joint whenever it touches the soil, making it difficult to pull by hand. In beds it can be controlled by diligent and consistent removal. Mechanical removal is accomplished by using a garden fork to loosen the soil about 3 inches deep and gently working the roots out.

To control ground ivy by chemical means, a post-emergent herbicide needs to be used. Pre-emergent herbicides do not work on established ground ivy.

My house faces west and I have a huge maple (I think it’s a Norway maple) in my front yard that shades out what would be the front lawn. The tree roots are very dense and I am having a hard time gardening under it. I would like to replace the lawn with some type of groundcover (low maintenance) and add ornamental and evergreen shrubs as well. Any plant suggestions for this situation?

I appreciate your frustration with the Norway maple (Acer platanoides). A popular neighborhood tree for their dense shade, they also consume great quantities of soil nutrients and water with their heavy-duty surface roots.

You can’t change the nature of the tree, so call a truce on trying to garden directly under it. Make sure any soil buildup or mulch is removed from the tree base and the “knee” where the trunk curves to meet the soil. This smothers the tree’s ability to absorb water and nutrients and fosters trunk and root decay. It also provides a hiding place for detrimental pests and fungal spores.

Rethink your gardening to begin at least 8 to 10 feet out from the trunk of the tree. Since surface roots gradually spread apart as they radiate from the trunk, you can amend the soil in the “pockets” between the roots to accommodate low maintenance plants. By moving substantially away from the trunk, you can also create areas of low berms to give some interest and elevation to your plantings. Remember once the canopy is leafed out, you have predominantly dry shade. This is important when selecting plant material.

Consider variegated and silver leaves when picking evergreen groundcovers and perennials as they brighten up heavy shade. Look for plants that bloom at different seasons. Planting several groups of early-blooming crocus bulbs will give spring interest before the canopy has filled in. However, you can intersperse other shade-tolerant groundcovers such as winter creeper (Euonymus fortunei ‘Silver Queen’), wintergreen (Gaultheria) with its red berries, and lilyturf (Liriope). There are short ornamental grasses, like hakone grass (Hakonechloa macra), blue oat grass (Helictotrichon sempervirens) and blue fescue (Festuca amethystina) with desirable colors and textures. There are a few spreading and low-mounding yews and junipers that a reputable nursery can point out to you. Also consider a hardscape element such as a bench or birdbath to give focus and interest to the heavy shade. There are also a number of shade-loving perennials that will have room to grow if you bring your bed out to the maple’s drip line. By doing so, you will open up your gardening options and plant selection.