Yellowing of foliage of poppies near the ground area where mulch was applied
Dry looking foliage at base of poppies despite sufficient rain fall
Certified GKH Gardening Expert
This is, actually, likely the issue. They are very drought tolerant, and will rot very easily. If your area stays wet, then you may want to consider growing these in container. The heat can also cause this. What is your climate zone? For now, applying wettable sulfur, and dolomitic lime can help condition the soil after a wet period.