I have a Nikon D5100 and for flowers I use it with a Nikkor 55-300mm that I bought separately. It works well, but it is not cheap! As it is not a macro lens per se, I can also use if for other purposes of course, like landscapes, ships in the distance etc.
I had used that lens when I took a photo of the sun at sunrise and by a pure coincidence I noticed that I could see the AR2192 sunspot when I zoomed in. (I remember I posted a photo here.)
