You'll get an item to use on it, but if you haven't got it, you aren't at the right point in the game yet. You'll need to travel down to Azalea, then up to Goldenrod, defeat the gym leader, and obtain a water bottle from the flower store. This is the item you need.
you get the squirtbottle at the flower shop and water the tree(which is Sudowoodo)
The wiggly tree is actually Sudowoodo. You need to get the badge in Goldenrod City. Then you go to the Flower Shop (next to the gym) and get squirtbottle. Use the squirtbottle on Sudowoodo and it will attack you. Defeat it or catch it and you will be able to get past.
You find it after you fight the wiggly tree.
beat the goldenrod gym then go to the flower shop in goldenrod and she'll give you the squirt bottle
In Violet City. Follow the path that's in between the house and the Market, go past the girl & Boy that are just standing there and you'll find it.
put the controller down and get a life!
If you're talking about the wiggly tree on the battle frontier, it's sudowudo. Use the wailmer pail on it and you can battle and catch it. After surf along the path and you'll end up in artisan's cave. I think there's a rare candy in there and a lot of smeargle.
go to goldenrod city get the squirtbottle spray it on the wiggly tree and you battle sudwoodo
headbut a tree
If you deafeat Whitney you get the squirtbottle next door and then you go past national park and you see a tree it`s not a tree its a lv 20 suddowodo you use the squirt bottle and then it will attack HOPE THIS HELPS
It is the Pinon [wiggly line over first N] or spelled Pinyon Pine Tree.
it's a sudowoodo, water it with the wailmer pail, get that in rustboro flower shop