I have used both red, black and grey lava and have not observed any real difference in growing. The red does seem to be a bit softer though, but I don't know if that is a characteristic of its color or the source that it comes from. Personally I'd prefer the darker colors as less obtrusive.
Lava colors are determined by the chemical makeup, and the impurities in it. Basalt is normally dark grey to black, but the cinders near
Sunset Crater for example, can be green or red.
This site has a lot of interesting lava trivia:
http://volcano.und.nodak.edu/vwdocs...group1_new.html
Regards,
matt