Someone once told me that silver dollar gum tree leaves gave a good orange dye. When I tried it years ago I just got yellow. Now I have discovered why. I added alum as a mordant but I Eucalyptus does not need a mordant at all.
Here is what we did to get this extraordinary terracotta red colour.
The Eucalyptus leaves give up their colour when they are heated. Some of the other people got amazing pink prints from this tree by wrapping the leaves up in wool or silk and boiling or steaming them. The prints are quite a lolly pink - amazing from a greenish leaf.
We also tried boiling up kowhai pods. We added iron sulphate as a mordant and it dyed bits of old woolen blanket a really dark army green. You can buy iron sulphate from the garden centre. I think it is used for killing moss on lawns.
Comfrey dyed the wool bright yellow with alum as the mordant. Next time we will try using copper as (hopefully) this should give us a lighter green.
Most plants give brown or yellow so it is nice to find some that give greens and reds.
About 10 years ago Prue Townsend gave me a bag of lichen which had been in the collection of Oriel Hoskin until she died. I tried using a bit of the lichen at the time and didn't get much of a result but decided to have another go. It looks like a native New Zealand lichen called Sticta Coronata but it doesn't turn pink when acetone is dropped on it, which is a sign of Sticta C. Apparently what you do with Sticta is you boil it up and keep changing the water. You dye fabric in each change of water and as you keep going you keep getting different colours. At the moment I am still at the brown stage. See below.
If you are trying this at home, don't use pots that you are going to cook food in, and preferably cook outside the house as the smell of eucalyptus or other plants cooking, can be quite nauseating.