Help! Border Invader

This plant is rampant in my neighbour's flower border, does anyone know what it is ?

when in flower it is small, creamy with a hint of pink. It spreads like wildfire by sending out black runners:

These form a mat across the soil as well as burying themselves just below the surface:

My neighbour says it was introduced to the border by his Ex a few years ago as a ground cover plant .... it has certainly done that as well as choking everything else, ornamental grasses included and it is making a determined attack on the rose bushes too.
I would like to know what it is, more about its origins and how it should be used in the garden.

 

It looks like Prunella vulgaris - hardy pernennal. As your said it is a ground cover plant, grow well in any moist soil. I treat it as weed.

 

Hi Vistabile. do you mean the flowers are creamy with a hint of pink? Prunella vulgaris is purple/violet but the growing habit of your neighbour's plant is the same as the mint family which fits Chengjing's theory. Yipee, something to talk about seriously. Come in experts.

 

Yes, Sarraceniac, the flowers are creamy with a hint of pink. They nestle in the foliage, unlike the mints which seem to bear theirs aloft, I doubt that it was aquired for the flower, they are hardly eye-catching. The leaves are also longer than any culinary mint I have seen, they grow to about 4 inches in length.

 

Don't think it's P. vulgaris then. But I don't know what it is. But someone will.

 

No, the flowers are definately not those of P. vulgaris .... pity because my neighbour's house was a local farm house and he prefers to grow varieties of native garden plants that blend in with the rural environment. I have a lot of respect for your gardening knowledge, John, and am grateful for your input. Further, I feel quite chuffed to have been beaten by a plant that has you puzzled too, maybe I am not such a gardening numbskull after all. Fingers crossed someone will identify it sooner rather than later, I am not sure whether to banish it completely from the border to a container of some sort, or to leave a patch at one end of the border and see how it reacts to next year's wet summer (wonder if that forcast's right?)

 

might be a form of ajuga (bugle). It spreads that way. Not so sure about the flower colour, though. Here's a link to some pics of the purple flowered version of it.....
http://images.google.com/images?q=ajuga&hl=en-GB&sourceid=gd&rls=GGLD,GGLD:2006-49,GGLD:en-GB&um=1&ie=UTF-8&sa=N&tab=wi

 

Can you describe the flowers - shape and size? Could it be one of the cultivals of Prunella?

 

Many thanks, dendrobium, I've looked through several pages of your link but have not come across it yet. Bugle seems to have a more orderly growth pattern, often rosette shaped. The Border Invader seems to have more in common with the Prunellas from that aspect. However, the flowers are not held proud of the foliage in the way bugles and prunellas do. My recall of details about the flower is not good, they do not catch the eye. They are about the size of a 2p piece and nestle among the foliage. I wish I had taken a photo when it was in flower, maybe its identification is going to have to wait until that is possible.

 

It is flowering !!!
Here is a photo ( sorry, photography is not one of my fortes): http://i116.photobucket.com/albums/o14/snikda/IMG_0008.jpg

The flowers are very similar to those of heather in size and shape but are clustered at the end of a short stem.
My research has come up with Shortia and Linnaea which share its straggly habit but neither produces its flowers in quite the same way, nor are their flowers the same shape (although there is a picture at the top of this Web page which is very close: http://www.cnplx.info/nplx/species?taxon=Linnaea+borealis+var.+longiflora).

What do you think it may be?

 

Your photo looks like a pulmonaria to me - but the leaves in your first pics don't!

 

I think the flowers resemble comfrey but the leaves are too small. I looked up Linnaea which does seem possible but it would be flowering very early.

 

It's a Symphytum (Comfrey), but not too sure which one - a bit of a fuzzy photo!

 

I think Comfrey too, I do have some but find it's easy to pull up what I don't need.

I use it to make a "smelly" liquid feed for my plants by tearing off the leaves and soaking them in water.

 

Doe look a lot like comfrey. I had the lovely big blue one as groundcover, but ended up using glysophate in the end.....