The flowers do look like a Verbascum sp. but the leaf margins are entire, which does not match either V. sinuatum or undulatum. It almost resembles V. bombyciferum except the leaves are not as pubescent. Hopefully someone familiar with the Verbascum that grow in California can help out here.
V. olympicum and V. speciosum also occur in CA, but at least according to CalFlora not in that particular area.
I don't know enough about what distinguishes those species from each other to say which one this is, but hopefully that helps to narrow things down. Of course if it was planted on purpose then it could be a different species too.
TomH3787 wrote:Hopefully someone familiar with the Verbascum that grow in California can help out here.
I'm sure any verbascum species one chooses will grow in California. Heck, I've yet to find one that won't grow here, so I don't think there is a particular exclusive list that one needs to refer to. ;-)