About Weld: answering a few questions

In the online workshop that Guida Fonseca taught here at Saber Fazer on June 20th, one of the plants used for dyeing was the Weld ( Reseda luteola), which also produces the most solid yellow of natural origin because it contains Luteolin, a special flavonoid. We grow Reseda every year and we now offer dried plants from our own crops in our online store, which we do in partnership with Quinta BioHabitus.
However, it is natural to find this plant growing spontaneously in certain areas of the country. The following questions arise from such a situation.

First of all, I'll give you the same advice I give at every workshop: I prefer the plants that will be used in dyeing to be intentionally cultivated, leaving those that are part of a natural system in balance alone.

Because I know very well that in order to dye larger quantities of fabrics or fibers, we need large quantities of plants and the temptation to harvest wildly is great. Even if each person harvests only a few plants, don't forget that (only) dozens of people are learning here!

After the online workshop, Teresa identified Resedas growing on her land. I advised her to collect seeds from these plants and cultivate them intentionally over the next few years. As they already grow naturally, they are sure to be very well adapted to the area and will need almost no care, which is exactly what we want! In the meantime, she can collect a few to experiment and understand their dyeing power.
As a result of the emails we exchanged, she asked me the following questions, which I'm going to answer here, because they help us understand a little more about this plant and I thought there might be people out there with the same doubts.
Here they are:

Q: I picked some of the resedas for seeds but I wondered if it was the right time. I think so, I can see little black dots the size of pinheads, but I was unsure...

A: Reseda seeds are little balls the size of pinheads. Yes! You can see them very well when they're ripe, because you can see the little black balls peeking out from inside the capsules that are positioned along the stem at the top.
You have to open those little capsules and let the seeds dry out a bit before saving them for sowing next year.

Q: What is the ideal time to harvest the plant for dyeing? Green? Flowering? In seed?

A: The ideal time is the end of flowering. This is the time when the upper tips of the plant still have a few flowers, but there are also ripe seeds at the bottom. As a whole, the stems, leaves and pods are beginning to take on a yellow color. When harvesting, the whole plant is uprooted and all the parts are used for dyeing, except the root.

Reseda luteola (Weld) seed

Capsules with ripe seeds inside

Capsules with ripe seeds inside

Capsules with ripe seeds inside

Resedas at the right time to harvest. The lower part of the stem already contains capsules with ripe seeds, but flowering is not yet completely finished.

Dyeing results from the Resedas we grow. One skein has the typical and unique yellow of Reseda. The other skein has undergone color modification with copper sulphate.

Q: My resedas are small compared to the images I've seen... The largest is around 50 cm long at most... I cut it close to the ground but there were few leaves.

A: There are many varieties of Resedas. The ones you have on your land are wild, which means they may be smaller than the ones you see when you search on the internet. Some varieties of reseda reach heights of 1.50m!
Resedas cultivated in richer soil grow more, as I've seen with my own plants, but there are studies that say that resedas grown in poorer soil produce more luteolin.

In other words, the size of the plant may not be directly related to its productivity.
Your resedas had no leaves because they must have been at the end of their cycle. I'm sure the seeds would have reached maturity by now and would have had almost no flowers.

The little resedas of 2018, but they didn't disappoint with the beautiful colors they gave us.

Wild resedas of about 70-80cm at their highest point.

Q: I've read that they're biennial plants, so that means they'll sprout again next year, right?

A: Biennial plants are plants that complete their vegetative cycle, from seed to plant to flowering, in two growing seasons. For example, Woad is a biennial plant: it is sown in the spring and remains in the ground, reaching flowering and consequent seed production only in the spring of the following year.

If the plant is wild, it “self-seeds”: the seed falls to the ground and germinates naturally at the right time.
When Reseda is harvested for dyeing, it is uprooted in its entirety, which means it won't “sprout” again. Hence the importance of growing our own plants and not over-harvesting wild plants, you understand?

The literature and the internet tell us that Reseda luteola is a biennial plant. However, the ones I grow, which come from seeds collected from wild plants (like yours), are annuals. When I grew them for the first time, I expected them to flower only the following year, but they completed the cycle in the same year: they were sown in spring and ready to harvest at the end of summer.

I chose to grow a local variety because I thought they would be well adapted to local conditions, requiring little dedication, which for me is equivalent to sustainability. With more dedication they grow bigger and better, but in the first year they were planted in a place without irrigation and they stayed there without any problems. This means that they are resilient and need very little water to grow.
In dyeing they have given excellent results, producing the same intensely yellow color, even between harvests from different years.
The fact that they are annual plants is a great bonus!

Reseda still in rosacea;

Reseda growing;

Reseda growing;

Reseda at its maximum height;