Baidu map is the best app you can use for local transportation, or you can call taxi from baidu app.
There are multiple public buses to Xixi wetland park, depending on where you are traveling from in Hangzhou.
If you can read Chinese, check the local web 'mapbar' or 'baidu map' for bus info (no VPN required). Otherwise you can always use 'google map' with a VPN connection.
Get quick answers from Xixi Wetland Park staff and past visitors.