They all turn white when it comes in contact with water especially, even the so-called clear gel-types. Just cut up some moss, and stick that on the glue spots, will look very natural as well, once the moss grows in. But even without moss, in time (2-3 months), the rhizome will cover up the glue spots.
If you're doing a dry start, glue isn't always needed, just stick it in some crevice (sp?) or tie some string on it; in 3-4 days it'll have grown onto the wood by itself, and you can just cut off the string.