There are 2 kinds of cherry in Zhongshan Park and Badaguan Area, which we called 单樱(single cherry??) and 双樱(double cherry??), sorry I don't know their English names. Most of the trees are single cherry I think.
In 2017, the best time was April 8-15 for single cherry blossoms; In 2018, I can't remember clearly, it was April 10-25.
Double cherry blossoms starts at the end of April or the start of May.