the city is big on osmanthus trees, last year they planted 1000 of them along certain streets.
Ficus microcarpa is quite common too. Various pine trees do well too, but be careful about using them in certain areas because chinese tend to associate those with graveyard.. probably because they use them to screen the graveyards from public.
if you have a mandarin reader, have them look at http://www.cdbpw.chengdu.gov.cn/
thats the government website on landscape planning, a lot of good information