Bushes are growing along river frontage in Northern California in partial shade. Rapidly growing plants now 1 foot to 3 plus feet high. Average full grown leaf 6" long 4-5" across. Hairy stems with prominently veined under leaf with light hairs the sting.
I wouldn't disagree with the Urtica dioica ID but to paraphrase Crocodile Dundee: that's not a nettle; this is a nettle: http://www.plantshots.com/img10906.htm Don't mess with Urtica ferox. To call it a stinging nettle would be a serious understatement.
Could it be Urtica urens ? The very long petioles of the lower leaves are suggestive. In U. urens they should be longer than the leaf blade.
