Help, advice needed on mystery plant

Hello,
This is my first post on a forum and Im after some advice, we bought our home a couple of years ago and the woman who lived here before was obviously a keen gardener. I dont claim to know much about gardening myself although Im learning and Ive managed not to ruin the back garden so far but Im having trouble with a particular plant in the front garden.
I dont know what it is and neither does my mother-in-law who is the only keen gardener I know. I was very suprised when she didnt know and originally liked it and asked if she could take some but after she'd witnessed how it takes over she's decided not to take any!
Two summers ago I pulled it all up however it came back fiercer, last year I was constantly maintaining and trying to control it but this year its almost taken over the front garden. Ive used Weedol Rootkiller+ on it this year and it just appeared to damage the part of the leaf that it landed on! Until now Ive found this weedkiller extremely effective and Im running out of ideas on how to get rid of it.
Ive attached a couple of photos, the first 2 are of the flowers and the plant, the second to show how its taking over the garden and the third shows the leaves and the damage to them from the weedkiller.
Any suggestions would be amazing, especially if somebody knows what this is?
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ekh_southwest

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wrote:

I can't help you on the plant ID, but I'm sure others will be able to help.
However, I would volunteer to ship you a package of apostrophes.
HB
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ekh_southwest said:

It spreads vigorously from rhizomes and also from abundant seeds. The key to control is to eliminate the top growth over and over again to deplete the rhizomes and to rigorously remove any new seedlings.
Bouncingbet has been officially designated as an invasive weed in Colorado (where my mother lives) which requires it be "either eradicated, contained, or suppressed" and the suggested control method is to "[h]andpull or dig only single plants/new infestations when the soil is moist" to ensure you remove as much of the root system as possible. The recommend herbicide is Chorsulfuron (brand names: Glean, CORSAIR, Telar) applied at "bolting to bud growth stage."
Link to Colorado website: http://preview.tinyurl.com/cn2ddj7
Other states have not gone as far as Colorado in restricting this plant, but it is a problem in Long Island, New York and parts of Michigan. (The Michigan Nature Conservancy has discovered thay glyphosate does not offer more than a 50% chance of control, at best.)
The best time to attack a plant like this is just as the flowers are forming, as the root reserves will be lowest at that time. Too bad it is so very invasive, as the flowers are pretty and fragrant.

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Pat in Plymouth MI

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It looks like a double-flowered form of Bouncingbet (Saponaria officinalis).
It spreads vigorously from rhizomes and also from abundant seeds. The key
to control is to eliminate the top growth over and over again to deplete the
rhizomes and to rigorously remove any new seedlings.
Bouncingbet has been officially designated as an invasive weed in Colorado
(where my mother lives) which requires it be "either eradicated, contained, or
suppressed" and the suggested control method is to "[h]andpull or dig only
single plants/new infestations when the soil is moist" to ensure you remove
as much of the root system as possible. The recommend herbicide is Chorsulfuron (brand names: Glean, CORSAIR, Telar) applied at "bolting to
bud growth stage."
Link to Colorado website: 'TinyURL.com - shorten that long URL into a tiny URL' (http://preview.tinyurl.com/cn2ddj7 )
Other states have not gone as far as Colorado in restricting this plant, but
it is a problem in Long Island, New York and parts of Michigan. (The Michigan Nature Conservancy has discovered thay glyphosate does not offer more than a 50% chance of control, at best.)
The best time to attack a plant like this is just as the flowers are forming,
as the root reserves will be lowest at that time. Too bad it is so very
invasive, as the flowers are pretty and fragrant.- -
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Oh, thankyou so much! It is a shame as they are lovely little flowers but it's taken over the whole garden. Im not sure if I can get those brands of herbacide in the UK but I will have a look, if nothing else it's good to know what it is and persist in pulling it up and I can start trimming off the top growth too.
Very interesting to know that it's designated as an invasive weed in Colorado too.
Thankyou very much for your help.
-ekh
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ekh_southwest


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