Where do you find squirtbottle?

Defeat Whitney and talk to the proprietor of the flower shop next door!

Defeat Whitney first, then go outside the gym. You can heal your pokemon. go back to the gym. talk to whitney. She will give u plainbadge. Go to the house beside the the gym talk to the lady. she will say her sister went to look at the weird tree. Go to the tree through national park. You'll have to battle lots of trainers on the way there. Talk to her sister then go back to the house beside the gym the lady you had talked to in the house just now will give you squirtbottle.

You can also do this before you fight the gym I think. But then you'll have to fight the gym before you get the squirtbottle you use the squirtbottle on the tree,it will be sudowoodo. Anyway, get the trainer's phone number below the tree. He will give you fire stone but u'll have to wait for a while then you can go to Eruteak.

I can help you by telling you that a trainer named tully who stands by the second pond before mahogony town gives you water stone if you get his phone number and a girl named Gina standing near the fence in a square surrounded by grass will give you leaf stone if you get her phone number. These three trainers will always give you the stones sometime after they give the first stone so I suggest that you keep them in your phonebook

Beat Whitney and talk to the girl in the house next to the gym.