We call those Chenopods!!! In the fall we rip them off the pine trees that they invade and thow the "pods" at each other -- makes for great family fun!!
But seriously they can choke out what ever they attach themselves to so get pulling!!!
"Remember this: Whoever sows sparingly will also reap sparingly, and whoever sows generously will also reap generously."
2 Corinthians 9:6