Goldenrod (Solidago virgaurea) is perfect for natural dyeing which can easily be added and removed from the dye bath - you could also infuse first then use the dye liquor for your natural dyeing.  Whole dyestuff is perfect also for yarn dyeing where you wish to avoid too many particles remaining in the batch. 
 
Goldenrod yields a yellow/green colour depending on quantity used, the fibres used, and the pH of your dye bath too (i.e. whether you use any dye modifiers such as acids or alkaline).  Mordants are required - Alum for animal fibres, and Aluminium acetate is recommended with plant fibres.  
 
Smallest pack size supplied is 100g
 
Recommended use is at least 100% weight of fibre/fabric (WOF).