I often plant and forget in my gardens! I think I planted some sunflower seeds last year which these might be? They are about 3 1/2 feet tall and growing fast! HELP! (I don't know why they are appearing upside down........or sideways.........they are nice and tall!
SOLVED: Tall lovely plantswhat are they?
Perhaps these are perrennial sunflowers. They also spread by root runners.
I agree with Suse, looks like sun choke/jerusalem artichoke. AKA perennial sunflowers. Helianthus tuberosus. Nearly impossible to get rid of. Invasive. Some people say they like the taste of the tubers (but I think they are horrible...the tubers, not the people). The tubers are noted for their fart-producing properties. Sorry, but it is true.