The chrysanthemum and cherry blossom are both national flowers of Japan. They’re also the names of the two plantations that “kiss” in Episode 5 of Darling in the Franxx, bringing two teams of parasites together.
Plantation 26 (chrysanthemum)
The parasites of Plantation 26 — one outburst at Zero-two aside — are stately and calm. They also occupy a unique position in the series, since they know a lot more about the world of Darling in the Franxx than both us as an audience and the members of Plantation 13. Despite this, they aren’t forthcoming with said information, although it seems to be more out of caring than spite. There’s the sense that the chrysanthemum parasites don’t want to spoil what the members of Plantation 13 do have — given names, unique franxx, blissful ignorance — despite not understanding them. “You guys are really unusual,” Plantation 26’s leader says. “Your franxx designs are all over the place, and you refer to each other as nicknames instead of codes. What’s the point of that?”
Yellow chrysanthemums are imperial flowers in Japanese hanakotoba. They represent the imperial family of Japan, whose seat — position of power, not physical seat — is called The Chrysanthemum Throne and a 16-petal chrysanthemum blossom is the royal seal, used in formal documentation. More than the ubiquitous cherry blossom, the chrysanthemum is the flower of Japan. The unfolding of a chrysanthemum flower is also said to represent perfection and is also used in some forms of meditation.
A flower of autumn, white chrysanthemums are important funeral flowers in Japanese culture. Red chrysanthemums are gifts for the person you love. Because there are so many varieties and colors of chrysanthemums, their meanings span the cycle of birth and new beginnings to death.
This is appropriate for Plantation 26, whose parasites have the same morbid acceptance of their situation as Zero-two. Why have individual franxx when uniform allows for easier fighting? Why give each other nicknames when you’re bound to die?
Plantation 13 (cerasus)
Cerasus comes from prunus cerasus, which is the edible sour cherry. Unlike sweet cherry varieties, sour cherries are capable of self-pollenization — they are basically self-fertile. Against the backdrop of genetics, floral reproduction, and even mistletoes, (which are not only a kissing plant but were used by Charles Darwin in his Origin of Species as an example of the struggle of survival) the fact that Plantation 13 is named for this specific variety of cherry is not a coincidence.
The parasites of Plantation 13 learn from 26 that they are an experimental test group. They have been given a modicum of individuality — both in their nicknames and their mech designs — that other plantations don’t have. Zero-two’s presence in their squad only exacerbates this — she is already a solitary individual and she ignores social rules. Although it’s a bit too on-the-nose, Zero-two initiates mixing between the young men and women of Plantation 13 at mealtimes due to her refusal to separate from Hiro. She drips honey over everything. Zero-two is the great pollinator of Plantation 13 and it’s also no coincidence that we see more co-mingling in this episode between individuals in Plantation 13, even if it’s rejected, like Mitsuru and Kokoro.
As the other flower of Japan, cherry blossom flowers (usually the Japanese cherry, prunus serrulata, but this also refers to all cherry varieties) symbolize spring, much like the chrysanthemum symbolizes autumn. Cherry blossoms are said to resemble the transient nature of all things, and encourage viewers to contemplate beauty and the ephemerality of youth.
Although the Plantation 13 parasites have been given more leeway socially, they are still bound by the same system. When Zorome asks whether anyone in Plantation 26 has become an adult, the confusion is palpable. No one becomes an adult. Yet, Zorome doesn’t know this yet. In this same episode we also see Hiro contemplating his own death. Darling in the Franxx has made it clear that Hiro isn’t likely to die on his third piloting like Zero-two’s previous partners, but Hiro isn’t privy to this information. Given his condition, it makes sense that he’s operating under the assumption that he will die in this next fight, but he accepts that as a tradeoff for being able to fly.