I'm still trying to find that exact answer myself. From what I've found so far, It seems federally mature means in a state of flowering. Immature is a rooted plant in vegetative state.
Grey area is in your certain state, what they consider to be immature. If a clone has root nubs, they could probably consider that immature.
In my county (Orange), the laws are same as state, which is CA. I can have 12 immature *OR* 6 mature plants and 8.5oz dried. So my gray area is in perpetual harvest... does that mean I can have 4 mature plants and 8 immature?
Then there's the other side of things.. if you have dried, hanging plants, I've seen people have their plants counted as mature when they didn't cut the roots before hanging, I have a friend caught with 20lbs of hanging plants without counting them because they had no roots and were not manicured or as the law says "Processed".
To be safe, don't manicure your plants until you're ready to smoke it or count it in your legal dried amount. Join a good coop in your area and trade clones so you can switch off giving extra clones you don't pick, and then getting clones from someone else to try a different strand.
Until the gray areas are finalized, be safe, follow county rules. Make sure your county says 6 mature *AND* 6 immature and not Or like mine.
