Cheryl
I found it's best to cut them, very late in the day and cut them slightly immature and let them open in preservative. I had the same problems last year that you're having now. It was trial and error.
This year I'm using Chrysal's Prof 2 Solution for hydrating purposes. It's wonderful stuff but haven't tried it with the Rudbeckia's this year, coz my crop is somewhat of a failure. Oh well. Also remember that Rudbeckia's are long day plants and that's probably what's affecting your stem length. I guess you could give em a shot of Nitrogen and see what happens.
Cheers - Kim
Billabong Fresh Flower Farm

Kim,
Thanks for your input. I did fertilize but perhaps they needed an extra shot. I'll try picking less mature like you suggested, and later in the day. I usually cut while it's cooler in the monring as after things dry off a bit. I used them in our exhibition, and one 1st place, but the next day they were all wilted. That was embarassing. I had to replace all the flowers in it.
Cheryl

That IS embarassing! Poor you!

The problem I've had with ALL rudbeckias is wilting right after cutting. They get over it but their stems re-stiffen in the wilted position, so I pack them tightly into a tall bucket when harvesting, so they hold each other up, then let them condition in that same bucket overnight. At that point, they're okay and last at least a week (for Cherokee Sunset and other doubles) and two to three weeks for the single types. I harvest into my homemade conditioner recipe. Maybe they'd be okay in water, too, I just haven't tried it. My customers usually got similar results with the Floralife Crystal Clear I handed out.

I've found the plants like less food rather than more - they get diseased here if I feed them well. That's probably a local climate problem, though.

Jeanne

Thanks Jeanne. It's funny how some of them seem to hold up and some wilt in a day or two. I'll let them sit longer in the conditioner and see what happens.
Cheryl