Green dye (or not)

I have decided to try and dye a rainbow, I have red, orange and yellow so the next colour is green.  Apparently broom gives green or yellow dye but, after a long process of chopping the plant into small pieces, boiling, straining and simmering, all I got was brown.

then I tried N.Z spinach.  The liquid was yellow, and the wool was brown.

Then dandelion leaves, the liquid started out green and then turned brown. Brown is an annoyingly easy colour to get

Camomile produced a yellowy green liquid, the wool turned a very faint yellowy green but it is the best so far.

and then I decided to move on to something else.