Answer: Black Eyed Susan's are generally considered annuals in your gardening region. The fact that they wintered over (must be very protected, or your winter was unusually warm) is a complement to them. However, they are short-lived plant. Since they resprouted but didn't perform well, it's probably because they are reaching the end of their lifespan and are petering out. I'd replace them with healthy new plants next spring.
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