Unknown plant growing very fast across beds
By Tommyboy1980
United Kingdom 
I'm seeing if anyone could tell me what this is, it's just started growing from nowhere and growing very quickly. As I don't know what's been planted previously as just moved into a new house I didn't want to rip out a perfectly growing plant (if that's what it is)
11 Jul, 2017
Answers
I agree it is one of the persicarias and if you don't like it weed it out. it is a free self seeder.
12 Jul, 2017
Good advice for a new garden is to do very little but remove obvious weeds and care for the things you recognise for the first season until you have discovered what's there already - takes a lot of will power! If yuo dig at this time of year you could be damaging things that have flowered in spring and disappeared until next year.
12 Jul, 2017
They pull out quite easily if you grab them from the base.
12 Jul, 2017
Previous question
« Good evening all, I've taken out 2 trees as they were too shady but I've...
Looks like Persicaria maculosa to me. I would consider it a weed in my garden. The wild plant has small pinkish flowers; someone else might know if there's a garden-worthy cultivar.
11 Jul, 2017