From its first episode, Darling in the Franxx uses flower language and plant genetics to frame the entire series. It’s not subtle about any of these trappings, which continue to appear in each passing episode week after week not only in commonly-used titles (like pistil, stamen, etc.) but also in flowers found in the on-site greenhouses, in various rooms, and the series’ most recent ending sequence.
Whether working directly with the language of flowers through naming schemes of the series’ mechs or framing its narrative with floral genetics and reproduction, Darling in the Franxx has never hidden its floral influences. It’s also not a subtle show, so when the entirety of Episode 8 is framed by Kokoro talking specifically about floriography — the flowers used for the robot names have always been present in the Plantation 13 gardens — the series is effectively painting a gigantic arrow that says “pay attention” pointed at flowers used within the show.
This is punctuated by an ending sequence that resembles Kiznaiver‘s, assigning a flower to each of the women in Darling in the Franxx. There are a lot of similarities between Kiznaiver and Darling in the Franxx — I’m personally inclined towards Kiznaiver since I think people generally have more trouble fumbling through empathy towards each other than sex — floriography being one of them. Where Kiznaiver used flowers as another frame of reference, dropping hints at the individual pasts of its female characters, Darling in the Franxx uses them unsubtly as possible, going as far to include this small shot at the beginning of this latest ending sequence, again telling us to pay attention.