There really should be a category for "flowers." as most of these roses are cultivated and therefore shouldn't come under "Nature." However, they're posted to make a comparison of suitable lenses for this type of picture.:
1) The first two are taken with a DA55-300mm fitted with a Canon 500T achromatic close up lens.
2) The next two are taken with a Tokina 90mm macro.
3) The last one is taken with a Sigma 17-70mm which focusses sufficiently close for this subject.

I'd say that all three lenses give satisfactory results, so a special macro is not required at this magnification. I was especially pleased by the IQ on the DA55-300 with a two element close up lens.

[noquarter15]

wow great work! beautiful shots

[cameraboy]

great shois a pity roses dont grow well in thailand it is most if the time too hot.great ian

[mel]

Nice. I especially like the third one.