薹とうが立たつ

expression, godan verb (-tsu)

go to seed; become tough and fibrous

Literally describes vegetables (especially leafy greens like spinach or rapeseed) that have bolted and become too tough to eat. Used for plants that have passed their edible stage.

• ほうれん草そうは薹とうが立たつと筋すじっぽくなる。

  Spinach becomes stringy when it goes to seed.

expression, godan verb (-tsu)

be past one's prime; lose the bloom of youth

Figurative extension of the plant sense, applied to people (especially women) who are considered past the peak of youth or beauty. Can be seen as dated or mildly sexist in modern usage.

• 彼かの女じょはまだ若わかいのに、周まわりから薹とうが立たったと言いわれるのが嫌いやだそうだ。

  She's still young, but she says she hates being told she's past her prime.