Compare to tansy ragwort, Senecio jacobaea.

hortster

Wickipedia says it is poisonous to livestock and has traditional herbal uses!

Here is a link that might be useful: Wikipedia

Oh great! According to this link, it's a noxious weed. I guess we'll be pulling it out ASAP!

Can we compost it prior to bloom, or is it bad stuff in compost piles?

Suzi

Here is a link that might be useful: California Noxious Weed

Hi Suzi - I don't know what this is but I can assure you it isn't Senecio jacobaea, aka Ragwort. That is a very common weed here and I know it well.

It is about to flower so if nobody gets it maybe you could post again with a picture of the blooms.

That's Phacelia ramosissima, a native perennial.

Senecio jacobaea has one or more erect stems from a taprootand leaves are smooth or have "loose wooly down on the undersides."
Phacelia ramosissima has many sprawling stems from along a rhizome, and the forms found in southern California (except those on the immediate coast) have densely glandular hairy leaves and stems.

i think it's Phacelia ramosissima from your description, and it's a native. There is a ton of it on our property, and we do need green stuff for the compost. It's an herb, right? So OK to put in there. Blooms should happen in a day or two. I see buds all over the thing.

Suzi

Seneceo jacobaea doesn't have a tap root. The roots are quite thick and fibrous. I've pulled enough of it to know, I'm afraid.

And you can put any plant on the compost - even Ragwort. (Not that this is Ragwort). The only no no would be the roots of persistent perennials like bindweed and some people don't put on seed heads.

Here is a link that might be useful: