Fox, I use this facebook group for any plant ID that I need. They are a huge group of botanists and plant nerds from around the world. They ONLY ID plants. There is no discussion of growing plants, plant uses, whether or not its invasive etc. just ID. and you'll usually get an accurate ID with in minutes. just take a few good photos of leaves how they are arranged on the stem. Where the plant is ( something more specific than 'Northern California') if you've got flowers or seeds show that. Then you can google away!
