Haha, Fly - I would gladly yank mine up if I could. They are a bone of contention w me. I wanted them gone but DH said it was our "only green", which is not true..we have desert willows, creosote and stuff. So I starved them of water believing they would die and I could innocently say, "oh, my..they died, tisk, tisk". They didn't die!!! Drought tolerant to the max. It froze one year wiped out tons of desert flora...but not these, oh no, they just kept living. I don't know if you really want to get them started...their pods go off and scatter like snake shot or something...pop! Ours grow up and onto a pergola that is over a back porch, which in-turn attract birds, adding to what falls from them. And, trust me, you do not want them to "join up" w your house. :) When DH wasn't looking...I stripped ever last leaf and stem off the "trunks" below the pergola "roof". Evil laugh..bwahahahaha!!
More info than you needed, I am sure...done ranting.
But, if you must plant them, I have notice that not a single plant has voluntarily emerged from the zillions of seeds they spew for which I am greatful - but it probably would take a rootball, as you say, to get them started.