The values need to be floats (in the range 0.0 to 1.0), not ints (in the range 0 to 255).
+ (UIColor *)colorWithRed:(CGFloat)red green:(CGFloat)green blue:(CGFloat)blue alpha:(CGFloat)alpha
Try:
[UIColor colorWithRed:136.0/255.0 green:155.0/255.0 blue:218.0/255.0 alpha:1.0];