Spring and summer are great seasons for planting and making changes in yard landscaping. The sewer clean out is probably the last thing people think of while doing yard work. While working in my yard I usually notice the location of the clean outs because I'm used to looking for them, but they are really easy to overlook.
Planting too close to a sewer clean out isn't a good idea because plants can spread as they grow and they end up hiding the clean out. If your plants have already hidden the clean out in your yard there are ways to find the sewer clean out. If you don't already have this problem keep the location in mind and try not to hide the clean out.