I can see what you were going for here and like your thought process, just as gramps suggested it doesn't have any context, doesn't tell a story or draw the eye in towards a subject.
The dark, moody and derelict convent scene seems to clash with the bright and cheery umbrella, and although in some cases they can create an intersting contrast or contradiction, in this case it doesn't quite work.
Selective colour is a little bit like extreme HDR, it can create a bitter taste in a lot of people's mouths! Perhaps mute the colours slightly so you're getting the colour across but it doesn't look so brazen. Here's one I've done where a lot of the feedback has been "I don't like selective colour however this one is ok". That's not to say it's the benchmark (far from it!) but it's often a little easier on the eye.
Furthermore I think slightly muted colours would enhance the mood of the old building that you're trying to convey.
Could I suggest you find a way of rigging the umbrella on fishing wire over the rafters (this might be further than you'd be willing to go!) so it sits right in the centre of the frame in the distance. Then you've created the context and the abstract visual image of the colourful umbrella with it's simple design and clean lines trying to float up and escape the dark chaotic mess.
Just suggestions, please ignore if I'm talking rubbish!
Good luck,
Dave
