That's even better if you have a local utricularia!! The use of native species in any aquarium can be a pretty cool thing! I'll be interested to see what it looks like once you've been able to incorporate it into your aquascape.
As far as mixing your plants: It is just what I am used to doing (separating plants into tight bunches). However, alot of "biotope" aquariums incorporate a lot of "mixing" as it makes it look more "natural." As long as YOU like the end result, that's all that matters!!
