Does anyone know what this is?
My wife doesn’t think she purchased it as either seeds or plant (she doesn’t pay a lot of attention sometimes) - so likely a weed of some sort, but it is pretty. It has no blooms (what you see are mums that growing in the same area), and has grown to be about 24 inches tall or so and quite well filled in.
Thanks!
It could be cosmos (not a weed) or scentless chamomile (weed). It may be that it hasn’t flowered yet. Do you see any buds forming at the ends of the branches?
Also, does the foliage have a scent (other than the regular “green” smell)?
Btw, those flowers are marigolds. 
I also suggest bruising or crushing some foliage. There are aromatic members of the genus Artemisia (like A. annua, or sweet Annie) that have ferny foliage.
Amsonia hubrichtii has similar foliage, but you probably would have noticed the blue flowers earlier in the season.
If you can’t solve it here, I’d suggest this free app for Apple & Android. You just take a picture with your phone and it identifies it. It’s worked great for me.
It looks a lot like dill to me, which is spared the title of “weed” only by virtue of the fact that it’s often welcomed. Call it a “volunteer” if you prefer.
Smell would definitely help with identification.
It looks a lot like Artemisia abrotanum
I can’t help with plant ID. But I’m curious why your title says " - cannot reuse titles I guess"?
Discourse has a nag screen that will say in effect “That title looks similar to these other existing ones, are you sure?”, but AFAIK you’re free to ignore the nag and post anyhow. IME the nag screen is real sloppy about what it considers “similar enough”.
Did you obey the nag or was it something more forceful where you were prevented from posting until you tweaked your title?
“Picture this” is another app that works
Does not look like dill to me.
What you will need for an ID is a piece of one stem with leaves, on a white or otherwise neutral background. Your photo is of a green hairy blob that could be any number of things. The best thing is a pic of the flower (many leaves look similar).
You might google Kochia aka Burning Bush or Burning Grass. (current Latin name Bassia Scoparia). It’s not a grass by the way. That could be it, particularly if there is no aromatic scent as dill would have.
Thanks for the help (the mum/marigold thing shows I needed it). The ‘Picture This’ app seems to think it is dog fennel when I snap the whole plant, and garden cosmos when I use a picture of just a stem against a neutral background. Definitely not dill, I would know that smell.
Going with fennel, because it has never bloomed at all.
And the title - I don’t remember if I actually tried to post a duplicate name (there is an exact match) or if I wimped out and just changed it.
My dad called it “dilly weed” when it grew in his garden. (And it wasn’t really a weed, there, as he’d planted it. But I guess it was a weed when it spread over the whole garden and had to be pulled out of the tomato patch.)
Can you show us a picture of a piece of it against a neutral background?
Almost all plants bloom, it’s just that some of them have tiny uninteresting flowers.
Well, this hasn’t bloomed in any interesting way, and the write-up makes it sound like it should have by now. This is the neutral background picture that came up Garden cosmos:
Here is a somewhat better “in the wild” picture, that came up as dog fennel on the app:
Fennel (Foeniculum vulgare) has ornamental bloom (sizable umbels of tiny bright yellow flowers), and dog fennel’s flowers, while individually small and white, are also produced in profusion and add to the decorative effect.
What the world still wants to know is, does the foliage have a noticeable fragrance when crushed?
Fragrance - not dill, but something that I would describe as noticeable but not awful (which leans away from the dog fennel). Still no blooms.
So, not licorice-y?
Rosemary is a relative of mint, a family which includes lots of different aromatic plants, There is a variety of different smells and leaf shapes, but I think that Rosemary is most likely to have a leaf like that. If it is Lamiaceae, flowers will turn up some time.
I pity the cops if you witness a serious crime, and they need you to give them a description of the suspect. 
Me too.
Years ago, a gentleman came to our door, said his car had broken down and asked if he could use our phone (which tells you how long ago this was). He seemed a little sketchy (but polite), I said no, he went on his way.
Very shortly thereafter, there are helicopters overheard and police with dogs and shotguns swarming the cul-de-sac. Guy was a robbery suspect, and had crashed his vehicle near us. I was sure I remembered what he looked like, but when a detective swung by and showed me pictures of 3 or 4 guys, none of them looked right (and I’m pretty sure the guy was in there).
Led me to be very leery of eye-witness identification, especially if any significant period of time has passed.
It is NOT rosemary, a very common landscaping shrub in California with a very distinctive smell (it smells like rosemary). It does not have a divided leaf like the photograph.
Without a flower, many plants are hard to id from a small internet photo. Including this one.
