Answer: As long as the stems are not discoloring and the foliage is not showing peculiar signs other than browning from the base up, I would still suspect a fungal infection such as mildew. To try to prevent it, Monarda can be thinned in early spring and should be planted in a location with good air circulation; maintaining an evenly moist soil also seems to help it fight off the infection. Removing any infected foliage and a thorough clean up in late fall can also help. Finally, some varieties are more susceptible to it than others, so you may want to look into some of the newer introductions of named varieties. One more approach is to plant the Monarda behind shorter plants so that you can't see the bare stems.
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