I HATE these things. I've spent the last two years battling them in my yard. I know many people consider them an asset since you can eat portions of them. Do not let them get in your yard unless you want them to take over. They spread by both rhizome and seed and have to be hand dug to eliminate, unless you plan to use multiple rounds of herbicide over several years. I have a literal 3 ft by 2 ft pile of them in the backyard that I've all dug by hand over the past week. They're pretty for some of the year, but can be a huge pain if they escape the pot!