I need drastic help! This plants roots are two feet deep and going every which way. Every tiny filigree rootlet turns into a plant. Three years of digging it out and trying to get rid of it, ends up with more and more of it.
I desperately need some advice on a way to exterminate this pretty flower that I feel will take over the whole 11/4 acres of my property.
Oenothera speciosa (siskiyou pink primrose)
Do you have a picture?
pictures of the plant are here: http://davesgarden.com/guides/pf/go/54831/
Have you tried spot on Round-up? If you can get the roots killed, maybe it will quit spreading. Just a thought
Roundup or a selective weedkiller if it's invading your lawn.