I like the dandilion- it could be cropped in a bit more, but I like that its not symetrical, centered on the green field.
The tulip images- I like the really closeups, when the background disappears- (very Georgia Okeeffe) The ones with green and selected cropped edges- the lip of the flower to the edge.. dont looked as intentional, more snapshotty.
Great color, can you play a bit more with the depth of field? like get a bit more definition behind the macro zoomy dandilion?
I really know very little about the equiptment. But will fling visual opinions with abandon.