Fairly authorative sources would be books used typically by botanists/biologists/ecologists/... to determine native plant species: these so-called 'floras' aim to include literally all native species, as wel as non-native ones which are fairly common and/or problematic. Principle:
- if it's mentioned in the book it wil either not explicitly state anything in which case it is a native plant, or otherwise will explicitly say non-native and perhaps specify additional details like whether the plant is used (and escaped) as a crop or garden plant
- if it's not in the book it is not native
Some of these books might also be available in digital form on a website (i.e. including the determination tables), and there might be official (state-funded) and other websites listing all these species as well but just not providing the determination.
Instead of turning to reading material you could also figure out which nature organizations are active in your area and contact them. Usually they'll already have answers on their websites for the typical 'how do I get my garden to fit into the local native ecosystem as good as possible' questions, because these questions are rather common.
I post this as an answer because it is too long for a comment, and know all of the above-mentioned material for my area, but the problem is I do not know which are the de-facto standard books for the U.S. (or better yet: for your particular state). This might help though: https://www.fs.fed.us/wildflowers/features/books/index.shtml. Likewise for the websites: a simple search for 'us online plant recognition' yields a ton f result but I cannot account for how well they work (i.e. can they correctly determine the species?) nor how good the provided information is.