Can anyone tell me how to KILL lily of the valley?

Where is the plant?

Start by digging up as much of the plant and its rhizomes as possible with a rake and then your hands. Then cover the area where your lily of the valley used to be with cardboard or layers of newspaper. Hold it down with something heavy (rocks, cinder block) and leave that there for about a season to smother the remaining seeds or rhizomes that may try to grow back. Good luck!

I would love to know. I think they are totally industructable.

Pour boiling water on it, that will cook the rhizomes!

roundup concentrate....but it will take years before anything will grow there again

Dig it up...guaranteed!

No round up, you may affect the tree. The only way I could do it was to carefully dig them up, even deeper than you think, a lot of the ones I dug up were attached to each other by roots. When I dug them up deep, they never came back. That way you no you are getting all the roots.

the rhizomes should be dug up first....these are nuisance plants that spread....one rhizome can produce a lot of plants...they are also deadly to animals or children who eat them....glad they can't grow in my zone....there should be a phone number for the manufacturer...call them first and see what ratio they recommend....I spray fence lines to keep prickley pear cactus from growing....mine is only lightly diluted because cactus need a stronger solution

Roundup but will kill everything. The plants have bulbs so could be dug up with lots of effort !

I heard you say that you mow them down. That's a mistake. That is like pruning them. I would go with the boiling water but then sprinkle salt on them. Use a whole box of salt. That usually works to kill just about anything plus it's all natural and inexpensive. Good luck.

Roundup. If close to other plants, brush it on. It'll kill darn near anything. May have to reappl. The stuff is pretty hardy.