Daisy, Daisy, Give Me Your Answer, Do

….. why won’t you grow for me??!!
I love these daisies. I think they might be Erigeron. They literally grow like weeds around here, in cracks in the pavements and walls and up steps, like these beauties.
I have tried to grow them but they don’t like it. I could buy a plant for around £2 but that seems silly. I shall persevere. Many people have told me to help myself to a clump and I have done so but, so far, to no avail.