How to Get Red Eco-prints with Eucalyptus

I’ve just released my new ebook all about eco-printing so I thought this might be a good time to write a quick post about the leaf that started it all for me, eucalyptus! I first learned about eco-printing in my natural dyes and weaving class in college over ten years ago. I saw an example of eucalyptus leaves printed on silk and I was shocked to see they printed a beautiful orange. It took me many years and lots of twists and turns before I finally got a chance to try the method myself and when I finally did...the results were terrible! I was so disappointed, but undeterred I began to scour the internet for answers to why my first attempts had failed so badly.

The following are the tips and tricks I’ve learned along the way to figure out how to get orange and red eucalyptus prints. My ebook covers how to eco-print with lots of different plants and goes in depth on mordants and how to use them in eco-printing, but this post will just focus on how to get those strong red eucalyptus prints. The first trick is to use protein fibers like silk and wool. Protein fibers are structured differently from cellulose fibers and they take eucalyptus prints particularly well without any help from a mordant. Eucalyptus eco-prints on plant fibers like cotton and linen as well, but they need the help of an iron mordant or other mordants, and the color will be very different than when printing on protein fibers. You can use an alum mordant or a soy binder on cellulose fibers to get orange prints but the results are different from the true reds that are possible on animal fibers. Don’t get me wrong, I love to print with eucalyptus on plant fibers, but the process is different from what I will cover here and if you’re interested in knowing more you can check out my new ebook here.

The fabric on the left is wool while the fabric on the right is cotton. Both are unmordanted and have been printed with different species of eucalyptus. You can see how the wool takes the color really well while the cotton only has faint prints.

The next tip is to use only certain species of eucalyptus leaves. It’s best to test the type of eucalyptus leaves you are using beforehand because not all species will print red or orange. There are over 700 species of eucalyptus trees and the colors from them vary widely. The first leaves that I ever used to eco-print with were Eucalyptus Globulus, also known as blue gum. These are great leaves to print with, especially when used with an iron mordant, but they do not print red. On protein fibers, and without a mordant, blue gum prints gold, tan, or brown. The results can be lovely, but if you were expecting red and instead get brown, the end result can be a bit disappointing. My favorite species that print red or orange, and are available locally here in Northern California, are Eucalyptus Sideroxylon (red iron bark), Eucalyptus Cinerea (silver dollar or argyle apple), Eucalyptus Polyanthemos (silver dollar), and Eucalyptus Nicholaii (peppermint gum). Of course, depending on where you live there may be different or more species that print these colors, and testing is the best way to know what is available around you. If you don’t live in an area where eucalyptus grows you may be able to source Eucalyptus Cinerea or Eucalyptus Polyanthemos from florists or floral markets as they are commonly used as filler in bouquets. Asking for the leftovers from weddings would also be a great way to reuse eucalyptus that would otherwise get thrown away. Another great resource for finding eucalyptus that print red is Sally Blake’s database of eucalyptus colors done in conjunction with the Australian National Botanical Garden.

Merino wool printed with peppermint gum leaves and blossoms

The third tip for red eucalyptus prints is how long you cook your bundle for. Most natural dyes don’t like high heat and will turn brown when boiled, eucalyptus is the exception to this rule. In order to print red (provided you are using the right species) eucalyptus leaves must be heated for much longer than most other plants used in eco-printing. The heat source that you use is also important. I used to use hot plates to heat the bundles for workshops but found that they never got the water quite hot enough. A gas stove or fire is the best way to heat bundles and I recommend a minimum of three hours of cooking time, but I’ve cooked bundles for up to 12 hours with great results, provided all the water doesn’t evaporate out of the pot. You can steam or boil the bundles, but because of the long cooking time I recommend boiling them or topping off your steam pot occasionally with more water to make sure the bundles don’t burn. A tight fitting lid also helps.

This silk was bundled with eucalyptus and steamed for 3 to 4 hours to get a nice strong red color

My final tip is to use fresh leaves or freshly dried leaves. Leaves that have fallen and been dried outside will have been bleached of their pigment by the sun. Make sure to use leaves that have been freshly picked (with consideration and respect for the tree of course) or that have very recently fallen from the tree (I like to go collecting after big storms). The leaves should still be pliable when you collect them. They can then be stored in water for up to 6 months, or dried in the shade and then rehydrated later when you are ready to use them.

Red iron bark leaves and blossoms that I had soaking in a bucket of water for 3 months before eco-printing them on a silk/wool blend

I have a whole section in my new ebook about eco-printing with eucalyptus, but these are some of my top tips for ways to get red or orange eucalyptus prints. I hope you’ve found these helpful, and I’m wishing you lots of luck and plant magic on your eco-printing journey!