Pick flowers that are open but not going to seed. Hang them in bunches, upside down. Once they're dry, put them in paper bags until you're ready to use them.
This is a very versatile dye plant! We got an amazing range of colors with goldenrod. Post-mordanting with iron really changed the color from gold to deep olive greens.
Goldenrod takes much better on protein fibers than cellulose fibers. Look at the top [left] card in the pic, right. That's cotton. Not much color took at all.
To dye with goldenrod, cut the stems and leaves off and let the flowering parts [fresh or dry] soak in warm water overnight. The next day, boil for an hour, then strain the plant parts out and put your fiber in.
Tip: Use quilt batt inside a large funnel to strain the plant material out. The polyester batts rinse clean and can be used during you next dye day.
