Texas Gardening: Texas Native Plant question, 1 by Dogs_N_Petunias

Dogs_N_Petunias wrote:
I gathered some Goldenrod yesterday. I cannot identify anything that looks like a seed. Maybe the wind has caused the seed to drop out already ??

PlantFiles says can be propagated "By dividing rhizomes, tubers, corms or bulbs (including offsets)." My question is: How and when?

I apologize ahead of time for asking what will probably be a lot of very elementary questions to most of you.

Glenna