Dog fennel. It may be good for bees and butterflies but it is one weed I don't hesitate to wipe out if I'm able. We had a back hayfield we rented out to a guy several years ago. There were three other fields included in his rental. Unbeknownst to us he decided not to harvest the hay off of this back field one year. Late the next fall I rode back there and a 35 acre field was so covered in dog fennel that you could not see a vehicle that was parked twenty feet into it.
That ended that guy's rental of the property. We rented to another guy and he got a free year's rent just to get the field back in some semblance of a hayfield.
Even more recently was the winter after I got sidelined from gardening due to getting hit by the truck...the dog fennel was terrible that fall/winter and a BIG chore for a dinged-up guy the following spring. The plants have sturdy rootstock and I guess are perennials but they also produce MILLIONS of seeds!!!
Below is a shot of my garden showing the dog fennel growing behind the electric fence...it took over in just a few months...from basically the end of June to probably sometime in September or October when frost hit it...the first picture is from December 15th. Not really impenetrable but those dog fennel plants produced an incredible amount of seeds. Prior to spring arrival I *carefully* (and with *lots* of effort) removed the stalks, roots, and *seedheads* that I was able to, trying not to disturb the seedheads too much. Regardless of my efforts the following summer gardening was a struggle against a carpet of dog fennel seedlings.
Dog fennel...no thank you!
Not even in a vacant lot.
