Eucalypts are native to Australia, Papua New-Guinea, and a few of the adjacent islands. The dye colors obtained from Eucalypts range from red, to orange, through to yellow, and olive green. Eucalypt leaves can be used as a substantive dye, in that no mordant is required to color the wool
Many natural dyes will fade unless the yarn is treated with a chemical to help fix the color. To improve light-fastness and to increase the range of colors obtained wool may be mordanted prior to dyeing.
My initial experiments were on wool pre-mordanted with alum. To test the dye color, use 50 grams (dry weight) of leaves to 1 litre of water and 1 metre of yarn. Simmer for 20-30 minutes to see what colour is obtained.

©1998 Margaret Rowe

 Here is a photo after my excursion into dyeing with some of the native leaves from the eucalypt family. You can have almost any color - as long as it's yellow (or orange)!