Debbie, the Marsh Marigolds tend to do that late in summer. Sad but they die back sometimes almost completely. Another thing I've noticed is they seem to be a bit more sensitive to the high ph, I have a very difficult time growing them. But the nice thing is that, their pretty yellow flower is the first thing to bloom in the spring and add color. This is why I also go around the yard and dig up clumps of violets and place them in the rocks in the margins, lots of spring color.
