Mine used to get all ratty after blooming, too. I used to cut them back to the ground. They always reseeded themselves and came back the following year.

Some of mine do this too, I just pull them up. They still re-seed quite aggressively. I believe that they are a “tender perennial” so some just up and die for whatever reason. I don’t worry about it, I still have to thin them out significantly come spring.

Thanks, all. I knew it was essentially an annual or short-lived perennial, but I thought it would at least still have some green foliage on it into the fall...oh well!

Sah,

Normally they do last the season. Something probably induced root/crown rot in that particular plant. I would not expect an epidemic of rot throughout your Rudbeckias, just an isolated case most likely. It was possibly responding to too much water.

I know how frustrating it is to have a plant fail right in a focal point of a flower bed, especially at this time of year when it is hard to get a replacement for it.

Maybe a nice fall blooming chrysanthemum could fill in the gap. Still, those so called hardy chrysanthemums are also rather short lived too. At least for the rest of the year it will do the job.

Don't give up on using R. hirta in your garden. The occasional failed plant is more than compensated for by the majority of these workhorse blooming machines that churn out blooms until frost. Just bear in mind that they are not long term perennials/biennials. Maybe one in five survives to bloom again next year. Survival to the year after that is a rarity, though. They are very reliable self sowers, a real plus.

Moses

Mine have typically died back after the seeds matured, about now on the earliest flowering plants, so it may just be responding to a combo of signals from a combo of shortening days and mature seeds.