Where is the rocket grunt in soulsilver that allows you to do cerulean gym?

The Rocket Grunt who allows you to do the Cerulean Gym is in the Goldenrod Flower Shop. Once you have obtained the Squirt Bottle from Bill in Vermilion City, you can spray it on the flowers. This will cause Oddish to appear, and when you have defeated it, the Rocket Grunt will appear and battle you.