When planting rosemary over or near a septic drainfield, will the root system invade the tiles that are 3 feet deep? Does this plant have a shallow or deep root system? My intent is to plant at least a foot and a half above the ground level.
Certified GKH Gardening Expert
Three feet deep should be deep enough to avoid damage from the rosemary. They don't have root systems that tend to be invasive as long as they get plenty of water.