You go the building next to the gym and get a spray can, after that you go to the tree that shakes and blocks the way. You spray it. it comes to live you battle it and done!
you have to go to the florest in golden rod city but before she will give it to you you have to beat the gym
beat the red gyarados ,beat team rocket where the seventh gym leader is to open the gym up, then beat the gym then professer elms gives you a call about golden rod radio tower, then you go there
go back to golden rod citygo to the radio station beat team rocket
Go to the Radio Tower and talk to the girl on the right side of the counter. She will ask you five questions. Answer them correctly and Whitney will come, compliment you, and run off to her gym. P.S. After you beat her she starts crying, lol.
go to the radio tower in golden rod
there is a flower house next to the gym. Go inside and talk to the girl she will give you a rod. Go to the weird tree, use the rod and you will battle it. Its level 20.
after defeating 7 gym leaders go to goldenrod radio station
im guessing you mean leave you go battle the black thorn gym
go to next gym
Go beat the fourth
You go to the Hearthrome gym
go and beat the 8th gym