Every spring... I have hundreds of volunteer hollyhock plants that practically take over my garden! They reseed easily (obviously) and have a long (very long) tap root... so the darn things are a pain to pull up. I love my old fashioned hollyhocks... I just wish they would stay in their proper place! I have spent all morning ... tugging on the darn things. I have one more section yet to do... but I am giving my back a break for the moment. This is not the only invasive plant I deal with each year. My lawn has mint growing in it that can take over if not weeded out occassionally. It does make the lawn smell good after mowing though! What do you have that is a bit too invasive? Have you come up with clever ways to manage these plants?