I'm sorry, I can't let this stand. There is truth there, yes, but then there's crap like yellow x red cosmos making pink. Could it happen? Maybe, if the yellow had white genes in it, or the yellow had red genes in it and the red had white, but does that make it useful information?
I say no, because it's misleading, and often it just seems like they were combinations that were put up there because some random person reported a spawn once. Maybe they didn't even correctly observe the parents, but either way, it's not productive to set up yellow x red cosmos if your goal is pink, because it'll only work if the genes involved, which you can't see, line up a certain way. You want red x white if you want pink.
In short, you want canonical parent combinations, which is much better represented elsewhere (though even with other sources you still need to read between the lines.) The rest is effectively chance, unless you're going super-hardcore and can definitively detail the heritage of any given flower in your town.
This is part of what irritates me so much about flowers in NL. The hidden genetic system is obfuscating the real information. I've spent a lot of time reading between the lines with various guides and think I've got a good handle on it, but still. We should be 100% clear on this by now.
We need some sort of DNA sequencer for flowers.
