Shiverthorn will not grow in planters

[Thomas Devlin]

I've had a patch of shiverthorn growing in my potion farm since the beginning of the game, but to this day not a single one of them has made it past the sprout stage. I have never had this problem before, and I'm not sure what the problem is. Does anybody know if there's a way to fix this?

[Smetrix]

Some plants will never fully bloom, so just harvest those ones and try again