The Nikon 40mm DX is made for that camera, is not that expensive, is very sharp. It also does not have such a shallow depth of focus as the 90mm. It does not have VR, but, the flower is not going anywhere, and in order to get the whole flower in focus, you have to have a small aperture, (and therefore, slow shutter speed, especially if you use a polarizer) anyhow. If you are really serious, you will use a tripod, so VR won't be necessary.
My problem with the 40 is that you need to get so close that it’s easy to cast shadows on the subject, sometimes even unavoidable. And yes the flowers don’t move, but sometimes you might try to catch a bee or butterfly in a flower and the distance is good so you don’t disturb it.