Why Wisteria flowers weren't a permanent solution against Demons in Demon Slayer, explained

The Wisteria Flowers in the Demon Slayer series hold a significant role as depicted in the manga and anime. Explained from the very beginning of the series, the Wisteria flowers work as a repellent to demons and prevent them from approaching humans.

While this may be considered an item of protection against the demons, it may not be a permanent solution to ward off demons. The use of Wisteria flowers mentioned in Demon Slayer, being both beautiful and effective, also might have a glaring drawback to the method that needs to be explored.

Disclaimer: This article contains speculative theory from Demon Slayer and reflects the author's opinions.

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Wisteria flowers are not a permanent solution in Demon Slayer

The role of the Wisteria flowers in the Demon Slayer series is very significant, especially when defending against demons. During the Final Selection arc, in episode 4 of the anime, titled Final Selection, the importance of the flowers was elaborated upon by the Ubuyashiki family.

The Final selection for the Corps took place on Mt. Fujikasane, a mountain surrounded by groves of Wisteria trees. As explained by Kanta and Kiriya, daughters of Kagaya Ubuyashiki, the Wisteria flowers grow from the bottom to the middle of the mountain all year round. They trap the demons within, as the demons hated the flowers.

As depicted in the series, the flowers contain a toxin that is harmful to demons, weakening and paralyzing them. It is also mentioned that the scent of the flowers is repulsive to demons, additionally making them avoid coming in contact with or within proximity of them. The use of Wisteria-based poison is a common trend among the Slayers, especially as seen by Shinobu Kocho, the Insect Hashira.

The venue of the Final Selection- Mount Fujikasane (Image via Ufotable)

The most glaring weakness that comes with the Wisteria flowers being a reliable solution for demon problems is the uncertainty of their bloom. While it was mentioned exclusively that the flowers grew around Mount Fujikasane all year round, there is no evidence in the manga that it is a common trait for the flowers.

Due to the lack of information provided in the series, if going by reality, the Wisteria flowers typically bloom around spring and last around two months. If going by that, the flower will likely fade after a certain time, leaving villages and areas wide open for demon attacks. This might also create the issue of holding back hungry demons who go on a rampage once the season ends.

Another scenario might also be that, due to the prolonged exposure to the flowers, some demons might gain immunity to them as well. Maybe that is the reason for not haphazardly planting the trees everywhere, but rather in just key locations like around the Corps' training ground and headquarters, and the Wisteria Family Crest house.

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In conclusion

The effect of the Wisteria poison on demons (Image via Ufotable)

Based on the explanation provided in the article, the idea of Wisteria flowers being a permanent solution in Demon Slayer can be discarded. While the flowers aren't the typical go-to for preventing and fighting demons, they do provide a layer of protection, especially for members of the Corps who aren't equipped for battle.

Withholding major spoilers from the Demon Slayer anime, the use of the Wisteria poison will be featured in the upcoming Infinity Castle arc, as the Hashira and several other Slayers make their way into the castle to stand against Muzan and his Upper Moon demons, in a final fight.

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