What is this growing within my patio?? I planted mammoth sunflowers last year and subsequent to it grew...

I planted mammoth sunflowers last year and subsequent to it grew which looks like a sunflower plant but nearby was no flowers on it freshly a weird green item growing out of the top. Well this year in that same nouns theres about 25 more high plants growing there. They look basically like sunflower plants soaring and same kinda leaves but no flowers just that grotesque green bunch on top. I tried lookin it up for days and I dont see anything like it.
Could it be an herb that looks close to that and grows that tall? Maybe whoever lived here earlier us grew something there. I own no idea. I dont want to pick it if its goin to be a pretty flower or something but later again if its nothing I want it out.
Tanks hope someone can relieve. Oh Im in interior california if that helps at adjectives.
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Answers:    Try looking up a Jerusalem Artichoke. It looks like something of what u described.
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Your sunflower could enjoy mutated. This is a defect where on earth the growth points go crazy and it sort of looks approaching a scallop.It is called critata.
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