Suggestions for steep ground cover in backyard?

Asked August 10, 2018, 4:37 PM EDT

I recently purchased a home with a very steep backyard that makes it difficult to have grass that would need to be mowed. The previous owners planted lilies as ground cover, however a substantial number of thistles and volunteer trees have begun to grow among the lilies choking them out. Given the incline, it is very challenging to pull these weeds. Do you have any recommendations on alternate ground cover that might keep the weeds back or methods to encourage the lilies to become thicker? I've included photos for reference. You can see in the "full view" image the left side has been weeded and right side has not. Thank you!

Hennepin County Minnesota

2 Responses

Thank you for the question. You do have a challenging location. The weeding you've already done is impressive and shows off the lilies nicely. Unfortunately, these is no way to encourage lily or other ground cover growth without controlling weeds first. Once the lilies expand to fill the bare patches vacated by weeds, they will crowd out most weeds and you should only have a few weeds to pull. The first weeding of such weed infested areas is always the hardest. Going forward, make it a habit to quickly scout the slope every few weeks and pull up new weeds. In this way, they won't get so out of control. In addition, the lilies grow best in full sun. Your site is partially shaded, so to encourage lily multiplication more quickly, you might consider pruning your trees to let more sun in.

If you want to plant a ground cover, you will need to devote substantial time and effort in clearing the slope of competing weeds, and then devoting several years to supplemental watering and weeding for the new plants to establish. It might be easier to encourage growth and multiplication of the lilies that are already present.

This publication lists many nice ground cover options: Be sure to choose those listed for zone 4.

Thank you for contacting Extension.

Thanks so much for the response! This is incredibly helpful. I'll continue watering and weeding. In the week since I've weeded it hasn't been too bad to keep it up. I am making sure to pull something everytime I walk down. I'll see how the lilies are able to fill in on their own over the next year, then make adjustments with the other ground cover options you suggest if needed.