Any Ideas Please

I've seen this before and have a feeling I should know this; I found it growing in a crevice at the base of the house wall in nothing more than dust (how it got there I don't know? seed carried by ants??). It looks quite attractive (even though it may just be a weed ) so I got it out and potted up the 3 seedlings that were growing side by side. Sorry the photo's a little blurred..

Thanks in advance

 

Persicaria, the best known is Red Dgragon, yours may be a smaller variety, Capitatum.

 

Thanks Strongy