Ask Mr. Smarty Plants

You didn't say what sort of plant these perennials are. If it's a large shrub, you may have to take more drastic actions, but if it's just a group of medium-size plants, here's what you do. There is no question of "planting over" the previous perennial, that just isn't practical. Just pull out (or dig out, if it's a shrub) the plant you don't like. Since you're in Michigan, you're probably going to want to go ahead and do this in the Fall, before it gets too cold. We recommend that you not do it before that, because you will want to replace it with your own choice of plants in the Spring, and there's no point in leaving a hole in your garden until then. Speaking of holes, while you have the soil disturbed from digging up the plant, consider amending the soil with some compost or other humus, mixing it with the native dirt and raising the level a little. This will help with drainage and your new little plants will thank you.

Also, while we have your attention, may we suggest that you replace that plant and make any other plantings in your garden with plants native to your area? The Lady Bird Johnson Wildflower Center is committed to the protection, propagation and increased use of plants native to the area in which they are being grown. Our area of expertise is North America. Since we don't know if you want a shrub, flowering plants, have sun or shade, etc., we are not going to attempt to recommend specific plants. If you go to our Recommended Species section and click on Michigan on the map, you will get a list of plants recommended for that area. You can Narrow Your Choice by selecting habit of plant, duration, sun or shade and so forth. Then, you can go to the Suppliers section of our website, type in your town and state in the Enter Search Location box, and fine native plant suppliers, seed companies and landscape professionals in your general area.