We just bought a house where the septic tank is in the front yard near the driveway. The previous owners put red lava rock around it and sat a big ugly flower pot on top. Do you have any suggestions for creating a flower bed or something more appealing to draw attention away from the concrete slab cover and make it look more like an intentional design element?
Without actually seeing the site, it's difficult to make specific suggestions. However, the basic way to disguise an unsightly element rather than to draw attention to it is to make it blend into a larger picture or design. For example, rather than mulching and planting in a tight circle around the tank cover, create a large free-form flower bed around it in which some vining plants such as sweet potato vine could clamber over the lid, softening its effect. Or perhaps add some concrete steppers through the garden leading to the concrete slab, so that it appears to be part of an intentional walkway.