The yellow poppy symbolizes wealth. This is due, in part, to a legend:

“It’s mainly due to some legends and stories that these meanings were attached to the flower.  According to a Greek legend, the poppy was the creation of the god of sleep.  Helping the goddess of corn when she lost her daughter, the poppies were used to sooth her to sleep.

If she rested the corn grew and because she fell asleep, the corn started to grow again.  It’s viewed that the poppies are essential to the growth of corn.  Corn is more than food but also a source of income.  That’s why yellow poppies mean wealth.”

Source:  https://www.auntyflo.com/flower-dictionary/yellow-poppy