While most of the time I use my Sigma 105mm macro lens for garden photography, one of my lesser used telephoto lenses is the Nikon 55-200mm f4-5.6 Non-VR Bought second-hand this lens rarely sees the light of day, but on the occasions I have used it, I have been pleased with the results.
Using this lens at the 200mm end actually makes flower photography that much easier, giving me more room to manoeuvre. The depth of field is more forgiving than the macro lens allowing me to capture the full bloom while still separating it from the background. It is also lightweight and gives me the benefit of other focal lengths if needed.
The lens itself does have one major drawback on the autofocus front. It is slow, very slow. Although slow to focus, it does seem to do a good job (given time).
The different viewpoint offered by the telephoto lens is completely different from that of the macro lens. While detail matters I find myself looking at the framing much more closely with the better depth of field using the background flora proved beneficial to the end result.
The Nikon 55-200mm non-vr lens is available second-hand for under £70 and proves to be a real bargain, and offers more flexibility in not just flower photography but in general usage as well.