Does the weed get flowers or seed stalks?

Where are you in Northern California? I assume you are in northern Central Valley or west of Sacramento where the people think they are in the northern part of California. If you live north of Redding (actual northern California) the answer to the weed question might be different. Also if you are coastal or in the mountains between Sac'to and Reno, the answer might be different. The Central Valley has its own climate which can trick you into thinking it should be cooler than it is for your latitude.

we are in central valley, modesto. I remember there’s a seed or flower last year of august and then they all died winter and now they grew up again.

You might try the Name that Plant forum on Houzz.