Reds and yellows are hard to get right. The red channel in particular can easily be blown, even if the blue and greens are in the middle of the histogram. I believe the red channel was probably blown in the second shot, with a loss of color. (apart from the white patch, the rest of the photo is fairly dark, yet the red channel histogram is way to the right, but that's after whatever post processing you did.

Not sure what color that first shot is supposed to be, but the yellows and oranges may also be blown.

In Adobe RAW I would do the following: move the recovery slider way to the right to bring down the bright background, move the blacks up to increase overall contrast, then use targeted adjustment brush to bring up the saturation (and possibly adjust hue and brightness) on specific colors (reds, oranges, yellows in this case).

Here is a quick attempt at the above (probably overdid the saturation on the reds):

You could also try a curves layer, with a mask and brushing onto the petals. Another way of applying some contrast or saturation locally without making the whole image garish.

I don't think the bright backgrounds are helping. I think you'd have more leeway in post processing if you had a more neutral background.

Oh, and the third one is fine, beautiful shot.