Answer: Your Bee Balm (Monarda) probably has mildew, it is very common on these plants. While it can be ugly, it ususally does not harm it permanently. The best ways to minimize it is to plant a resistant variety, thin it out at the base in early spring when the shoots first appear to enhance air circulation, and be sure to keep the soil moist. Now that it has finished blooming, most gardeners would deadhead it for appearance's sake. You may cut it back by about half now, too, if you wish, although it is not necessary. In fall after hard frosts, cut it to the ground and remove and destroy all the dead top growth. This will help minimize the mildew next year, too.
I'm not sure what happened to your Black-eyed Susan, but a common reason for just one stem to die back to the ground is that it was injured at some time. Assuming the little round ball things appear to be inert, they are probably a long-release fertilizer applied by the nursery. They will disappear over time all on their own.
Good luck with your plants!
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