How do I plant flowers in the beginning of the game?

How do I plant flowers in the beginning of the game?

In various guides I see the same advice:
The [Gardening] store opens five days after the player has created their
town. The player must also pull weeds and plant flowers a combined total
of 30 times.
But the gardening store is where I buy flower seeds so... how can I plant
flowers before it opens?