Actually, Shane, moving back would make it worse.
The general problem with a flash is it effectively a point light source - unless it is very close to the subject indeed. This results in harsh light - high contrast, dark clearly defined shadows, loss of detail in the highlights, etc. Now, this may be fine if that's what you want, but generally for nature macros, a soft more even light gives a more pleasing image.
Moving the flash further away (by moving back) makes it even more of a point light source. There is an added problem that if the flash is mounted on the camera, the effective gap between lens and the light source narrows.
For product photography and portraiture you generally try to make the source of the light as large as possible. The best way is with a soft box but it can also be done with bouncing the flash off the ceiling or walls. I'm sure you would have seen the effect and how much nicer the image looks. The same thing goes with macros, although bouncing the flash is not always possible. This is where a simple DIY softbox can help.
A DIY soft box takes the light from the flash, spreads in on a surface (like a sheet of paper) and uses that to light the subject.
I have three different ones I have made: A
large one for use at home with larger subjects; a
collapsible version of the large one, and a
small one for use with small subjects and higher magnification.
Try one, you'll be amazed at the different they can make.