Where the lists came from
Systems of correspondence (linking plants, planets, colours, metals and qualities) run through Renaissance and early modern occult writing, and modern witchcraft inherited that habit through ceremonial magic and twentieth-century Wicca. Popular correspondence tables published from the 1980s onward compiled and standardised material from many sources, which is why so many books agree with each other and occasionally with nothing else.
Why the lists disagree
Different books assign the same herb to different elements, and both will sound confident. That's a sign of what correspondences are: a shared symbolic vocabulary, useful for focusing intent and communicating with other practitioners, not a table of physical properties.
Building your own
A method suggested by Pretty Little Wiccan: choose an object or plant you already have a relationship with. Write what it smells and feels like, what it reminds you of, where you first met it, and one word for what it does for you. That word is your correspondence. It will outperform a memorised list every time, because you'll actually recall it under pressure.
Personal versus shared
Keep both. Note the conventional association and your own, side by side, in your Book of Shadows. When you work alone, use yours. When you're working with other people or reading someone else's spell, the conventional set is the shared language that makes the thing legible.
When personal meaning conflicts
If rosemary reminds you of a difficult person, that outweighs a book telling you it's for clarity. Use something else. The point of a correspondence is to concentrate attention, and an association you have to argue with does the opposite.