rudbeckia goldsturm - how to collect/sow seed?

Perhaps the seed needs a period of cold in the refrigerator for them to germinate. Try putting them on a damp (not wet) paper towel and then into a ziploc bag and pop them into the fridge for about 2 months. Keep checking them to make sure they don't start to germinate. After the 2 months, bring them out and sow them onto a good seedstarter mix and barely cover with soil or vermiculite. Put them somewhere warmish with good light and see what happens.

Hi Daiwelshman just checked and they need 3 - 4 weeks at just above freezing, so fridge would work (using the method Gilli advised) then again following Gilli's method a temp of around 22˚C for a couple of months to actually germinate. Good luck - let us know how you get on...

I have these in my garden Daiwelshman....and they are such thugs! I keep having to pull them up as they multiply by sending runners just under the surface of the soil, suffocating anything in their path. Such a lovely late summer flower but it overtakes everything. If I were to plant it myself I would keep it in pots sunk in the garden. I'm so surprised that you haven't them everywhere!