A bit of fun history
Rhamnus frangula aka Frangula alnus, commonly known as alder buckthorn, glossy buckthorn, or breaking buckthorn. Unlike other "buckthorns", alder buckthorn does not have thorns.
The word frangula is derived from the Latin "frangere", breaking and refers to the fragility of the wood. The Dutch name "vuilboom" (foul tree) is related to the unpleasant smell of the fresh bark, although it is sometimes claimed that this name has to do with the laxative effect.
The the simultaneous vomit inducing and laxative effect of the fresh bark is what the adler buckthorn was best known for in the 16th century. Popular belief explains, that the bark would have a laxative effect when peeled from top to bottom, and would induce vomiting when peeped from top to bottom. In the past, the buckthorn tree also found application on a completely different terrain. The wood provided an excellent quality charcoal, (thanks to the low ash content) which was used for the preparation of gunpowder. In Germany the alder buckthorn tree is still called "Pulverholz".
In my home country of the Netherlands (and anywhere else in Europe) this shrub/tree is very common in the woods and near the roads, but like with so many things of my youth, I would not have had the faintest idea of its' potential.
Dye Potential
The ripe berries of alder buckthorn give a blue and a green dye, and are used to make ink by boiling ripe buckthorn berries and combining that extract with alum and wine and thickening slightly with Gom Arabic.
See also this blog about ink making using buckthorn berries.
The bark; Dominique Cardon lists the active dye component in Alder Buckthorn as Anthraquinone.
I found indications the alder buckthorn bark is one of the dyes that was used already during the iron age in northern countries such as Scotland and Alaska to make red. Read a fascinating research about late iron age dyeing in Finland here (196 pages, free download).
The ancient Finnish dye samples were dyed with fermented alder buckthorn bark, indicating no heat was needed to get the colour out, so I started with a cold overnight bath with 50 grams of alder bark. I added soda ash to get an alkaline environment (just like I would have with madder). The Ph in all the samples is around Ph11.
Fabrics used
For this dye experiment I used the following fabrics;
Since all my wool and eri silk is already pre-washed by the supplier, I did not need to scour them before dyeing. Alder Buckthorn bark dyes well without any mordant, so no mordant was used here. Some extra experiments with different mordants will be saved for another day
The dye process
First bath. The cold dye bath gave great orange reds. 25 grams of bark soaked for two hours in tepid water, left overnight with fabric swatches. Soda ash added just enough to make the bath an alkaline Ph11.
Samples washed and dried.
The bark pieces in the dye water did not create any stains on the fabric.
Second bath. I took the samples out and started to heat the dye bath to 60ºC for about an hour. Cooled down, washed and dried.
Third bath. The last round I heated the bath to 80ºC for an hour. This is still the same bark that dyed three rounds, and still it has tons of potential for dyeing more.
It seems that the best reds would be on wool, when the dye is heated for 60ºC for an hour.
Side by side different baths on the same materials;
Wool cold, 60ºC and 80ºC.
100% Modal cold, 60ºC and 80ºC.
I will gladly start using alder buckthorn as an easy alternative to madder, not having to mordant the fabrics cuts a time consuming and water intense step I welcome very much.
The alder buckthorn bark would be a fun material for solar dyeing, or a slow tie-dye project on a cotton shirt.
For dyeing with Alder buckthorn on cellulose fibres see here.
PSA: the earliest lightfastness tests are showing me that this is rather fugitive on cellulose, and you should really use a mordant such as alum. On wool and silk the results are better, alum still improves results a LOT, use 20% WOF alum.
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