Japanese Indigo - That Irresistible Blue

This spring I sowed some Japanese Indigo. I have done that once before, but only really got one plant to live, but this time I had about eight healthy plants.

They got off to a slow start in the cold and wet Icelandic spring, but once I figured out that I really shouldn't expect a summer and covered them with fleece, they took off and turned into a vigorous bunch.

I harvested them all at the same time in fall and dyed some Alpaca wool with the thought of giving it to my daughter who wanted to make a simple garter stitch shawl.

Here is the method I used. A tutorial of sorts.

I cut the plants, stem and all and take them home.
I remove the leaves from the stems and chop them finely. I do this immediately after I get home. The leaves do not keep well and can not be dried.
I stuff the leaves into a jar and pour fresh water from the tap over the leaves. I put the jar in a pot - I always put a washcloth in the bottom of the pot - and heat it gently to 50°C / 120°F.
Then I sieve the liquid and squeeze out every last drop from the leaves. This time I actually felt that there was more colour left in the leaves, so I pout some more water on the leaves and heated them again. Just to be sure that I got every molecule of indigo into my dye liquid.
The resulting liquid was dark, dark blue. I was thrilled.
Then it is time for the stick blender to add air to the solution. This developes the indigo, although it is in an insoluble form. So the next step is to make the indigo water soluble...
...by adding hydrosulfite or spectrality or colour remover. I sprinkle about a teaspoonful over the surface and wait 30-45 minutes to see if the liquid turn to yellow. If not I add some more. Here I had moved the dye liquid to a pot so that I could be sure to keep the right temperature. I most often put the pot in another pot and heat that. This way I can control the temperature better.
When the liquid turns a green yellow I can carefully add the wool while I am careful not to introduce any air into the solution. I am careful to have wetted the wool really well before. That means I let it sit in water at least an hour before I dye it. And with wool and indigo, I make sure that the wool has been sitting in water that is the same temperature as the indigo solution (which is 50°C). I any air into the solution.
I let it sit for 10-20 minutes to get a dark colour. Shorter time for a lighter colour.
Then I pull it up gently and watch the magic transformation. It very quickly turns a lovely turquoise colour, but that is short lived. The colour soon developes into the indigo blue.
I shake the wool to air it properly. Then I let it sit for at least the same amount of time that I let it sit in the solution to fully develop the colour.
And then I re dip the wool or put another skein into the dye liquid until all the colour is gone. The colour gets progressively lighter. But all of them beautiful.

It is very hard to get the japanese indigo to flower in the northern hempishere. But I still have one plant left that I took inside. It hasn't flowered, and I may just cut it down soon and dye from it.

It's such a lovely blue.