perhaps it was a teasel
Common Teasel: Dipsacus fullonum

A plant with white flowers instead of the usual color isn't an albino plant, but rather a "variant" or "sport" with odd flower color. I am not sure that there are albino plants, and if there was a plant that lacked color it would also have to lack green chlorophyl, and therefore could not make food for itself. Such a a plant would never grow past the early seedling stage.

It seems to me that plants with red, pink, or blue flowers are more likely than yellow or orange-flowered plants to produce the occasional white-flowered seedling.

speaking of that, i found a sky blue tall ironweed today! normally they are a deep purple. i collected some seeds in hope to get that mutation growing.

lol sorry! lots of people mix them up and i thought may have been the case.