I really love symbolism in dramas and I really love this drama and since I'd noticed the recurring theme of sunflowers in episode 11, I had to look into possible meanings and symbolisms of sunflowers both in general and in Thai culture. Take this with a grain of salt because I'm not an expert in flower language, this is just a result of my 30 minute article read-through and lots of imagination.

So to introduce sunflowers, they're most commonly described as the flower of loyalty, devotion, resistance, longevity, prosperity, admiration and in Thai/Asian culture they're also known as the flower of transformation and a new beginning.

First we see a vase in Duang's room with a single knitted sunflower in the table as they're leaving Duang's apartment. Here I'd say the sunflower symbolises Duang's loyalty and devotion as he leaves the apartment to accompany Qin to the showcase. Notice how there's only one so far.

Then, Qin receives 4 sunflowers from his parents. In Thailand, sunflowers are given to celebrate achievements as a symbol of cheerfulness and optimism and Qin's mom specifically chose them as she views Qin as an optimistic and cheerful person. Maybe you could say there's something about Duang being the one who ultimately brings the bouquet back to Qin's apartment, as if he is the one bringing the optimism and cheerfulness into Qin's home, not Qin's parents and not Qin himself. Also, sunflower bouquets are apparently brought to hospitalized patients in Thailand as a "get well soon" wish and I can see that as a wish for Qin to be able to begin healing from the emotional negligence his parents had treated him with. From a narrative POV.

In the next scene Qin briefly glances at the bouquet after Duang tells him he loves him and gives him a present. This is the symbol of transformation and Duang's admiration, Qin is realising that even if his parents bought them, Duang is the one who brought in the sunflowers just like he brought in the love Qin never felt from his parents.

Qin's parents come to visit. There are 3 sunflowers in the vase, Duang knocks them off as he rushes to comfort Qin. A clear statement of Duang bringing change into Qin's life, knocking off the sunflowers Qin's parents got him while rushing to be the one at Qin's side.

And this is probably a stretch, but the one flower missing from the original bouquet? That's Duang and his devotion to Qin. He is truly Qin's one and only sunflower, the only one that stays in this scene.

The sunflowers are back in the vase after Qin's parents leave the apartment after they have come to understand him. I believe that after transformation, this is the symbol of a new beginning. Qin has accepted his parent's promise and let the sunflowers stay in his house after his parents had left.

And in the next scene, next to the bed, it's pretty much the same - sunflowers represent the cheerfulness and devotion of this scene and Duang is Qin's sunflower. Also, now there are only two of them and I have to share something I'd read in one of the articles. When you have two sunflowers, during the day they're both joyfully looking at the sun, but once the sun sets, the flowers fall down and look at each other. And I think that describes Duang and Qin's relationship beautifully, they share their happy moments, but also devote themselves to be with each other once those happy moments pass.

And then we don't see sunflowers again until... the final scene! And it ties so wonderfully here because ONCE AGAIN we see artificial sunflowers instead of fresh ones and once again they're in Duang's room, just like at the beginning of the episode. Except this time, there's not only one, but two of them, one for Duang and one for Qin, portraying their lasting love that will not wither like the fresh flowers would. I believe that this scene combines all the possible meanings of sunflowers from the past scenes, to show the loyalty and devotion they have for each other, the longevity and prosperity of their love and the transformation into a new beginning as they're moving forward and realising just how perfect they are for each other.

The sunflowers in this episode show the growth of Qin and Duang and they're like a hope for us viewers, proving to us that their story will be full of joy and support and will last for a very long time even if they won't be with us after next week's episode.