Shidare can mean "weeping" or "drooping" - something with branches that hang down. A number of different varieties can take a weeping form. Ume (flowering apricot, Prunus mume), cherry and willow can all be shidare. Was there another name besides shidare?
The flowers look like they could be ume but the leaves look different. That said, it's hard to tell from the photo.
As for the three colors, I'd guess the tree has been grafted.