Long distance bus schedule from Guangzhou to Yangshuo

So far I have only taken the bus from YS to GZ but in August I'll return to China and plan to fly into Guangzhou, then take the bus to YS. At what times do busses run from Guangzhou (Huanshi West Road next to the Railway Station) to YS? I will probably land in Guangzhou in the late afternoon (4pm) so I'm not sure if I should spend a night in Guangzhou or if it makes sense to hop on a bus the same evening.