By Hollowbaron
Essex,
United Kingdom 
What plant/weed is this? I've had these same plants appear in my garden. They grow quickly and form a thick trunk like a tree. The roots are really shallow though and are easy to pull out.
Before this one growing in neighbours garden, I've never seen one in bloom.
There are no branches or leaves near the bottom. Sorry I could not take pic of entire plant/weed.
4 May, 2014
Answers
Looks like a tree mallow (Lavatera?)
Nice colour. Flowering well.
4 May, 2014
Definitely a mallow they grow well and keep flowering until October I always trim mine after this time as they will always grow up the following year
5 May, 2014
Abutilon x suntense maybe. Even a tree of that size is shallow rooted and we had to stake the other halfs this year.
6 May, 2014
Check it on Google images under Malva sylvestris. Possibly subsp. maritima. I think you will recognize it there.
6 May, 2014
Thanks for answers
13 May, 2014
Looks like Common Mallow, Malva sylvestris
4 May, 2014