Anagallis arvensis - Scarlet pimpernel weed it is usually an annual belongs to the primrose family.

Weed!!!! Oh no!!!! It's really pretty. Does it spread? Can I keep it and can I grow it as a flower or will it be a pain in the watsit?

Well its mostly an annual - so keep it and enjoy it, if you let it set seed it will probably self seed for next year. I find them in the shady parts of my garden, as a youngster it prefers light shade. A weed is only a plant in the wrong place - so enjoy,

Thanks Drc726, I think I'll keep it as it's so pretty. I love plants for free too, so I'll let it self seed for next year. Are they any good in a sunny spot?

I dont know I have only ever pulled them up in between shrubs and tall plants. But whatever yours looks happy where it is.

Greenfingers, if you like your scarlet pimpernel you call it a wild flower and enjoy it. Weeds are only plants you don't want. A potato in the rose bed is a weed..... a rose in the potato bed is a weed. Anything you have too much of is a weed. You may well end up with too much scarlet pimpernel, in which case you can pull up the ones that are in the wrong place for you. I find they grow in sunny spots in stony soil.

It is generally regarded as a wild flower, but all plants were wild at some time in their history.
It was at one time more common and has become harder to find in recent times, people don't always see the good side of the plant and treat it like an unwanted guest/weed. A shame, because as you say it is quite pretty, not all garden plants have to be big and brash.

common name up where I grew up is 'poor mans weather glass'. it opens in full sun and closes depending on the amount of shade /cloud cover you get. I used to find it in open sites near the sand dunes as a kid.