I grow them deliberately, from bought packets of seeds, while my husband grows them by accident, spilling bird seed when he feeds our cockatoo.
Yours look great Dee-O-Gee , and you've a lovely garden by the looks of things. Not a weed in sight - you should see the weeds here. LOL.
I am about to plant sunflower seeds now and have some new types this year, which will be interesting.