By Speedy21
Gloucestershire,
United Kingdom 
We have this strange plant growing in the garden and we'd like some help to identify it,please.
It looks a bit like a mallow?? but it's 10 feet tall and growing with purple flowers.
4 Jul, 2012
Answers
Lavatera arborea I would say.
4 Jul, 2012
aka ... Tree Mallow.
4 Jul, 2012
Hi,Bamboo,I don't think it's an Hibiscus as we have several in the garden and this is totally different.
Fractal Cat,thanks for that but we do not think it's a tree mallow as we know where there are 2 already growing and we're not sure but they only come in pink.Please correct me if I'm wrong.
Speedy21
4 Jul, 2012
Fractal cat is right - the leaves confirm it. Slapped wrist for me for not looking at the foliage properly ....
4 Jul, 2012
Same family Bamboo...easy mistake to make
Just think it's a normal Mallow (Lavatera sp)
4 Jul, 2012
Yes, but I know well the foliage is important. Still never mind! Speedy - there are other colours than pink in this plant - there's one called Burgundy Wine which is similar to yours in colour, but not the size.
4 Jul, 2012
It's lovely!
4 Jul, 2012
Been trying to find this one - its an absolute minefield, there are so many cultivars of Lavatera. Haven't found one that looks like this though, well, not at that size. Most also have grey green leaves, where yours appears to have just green leaves.
4 Jul, 2012
Looks like Malva Sylvestris. And if it is, it reseeds beautifully.
4 Jul, 2012
Can't be Sophie - I know it looks a bit like it, but Malva doesn't get ten feet tall...
4 Jul, 2012
It is Malva Sylvestris. I have been growing them for a while, but this year, mine are 10 ft tall too! Must be the weather!!
4 Jul, 2012
Really, Kassi, I'm stunned - I've got Malva downstairs, but its only 3 feet, as usual.
4 Jul, 2012
Never mind Bamboo, it'll soon be upstairs as well :-)
4 Jul, 2012
The flower looks just like my malva, the leaves look just like my malva's, and if my malva is going to reach 10ft in the future that will be fantastic.... ;-)
4 Jul, 2012
LOL, I doubt it Andrew - its been in 5 years, and never made it past 3 feet... and disappears in the winter.
4 Jul, 2012
Many thanks to all who have contributed to this little conundrum,it's fascinating 'talking' to you through this medium.
We are beginning to form a more solid idea of what it is.
Speedy21
5 Jul, 2012
Speedy, does it disappear below ground in the winter, or just drop its leaves, leaving a woody framework above ground, particularly at the base?
5 Jul, 2012
Bamboo,we don't know what is going to happen as it has only this year.
I sent photos of it to our local BBC Gloucestershire Radio gardener,and all he could say it was some kind of mallow & he did not believe it could grow so tall!!
Some garden expert.
Speedy
7 Jul, 2012
Are you saying you only planted it this year?! And its made 10 feet since you did? Good heavens, didn't come with a copy of Jack and the Beanstalk, did it...
7 Jul, 2012
Bamboo,we never actually planted it,it just appeared.Must have been dropped by birds or came in a bag of compost.
Speedy
8 Jul, 2012
If it was 3 or 4 feet at most, then it could be Malva - but at 10 feet, I've no idea. See if it disappears completely during winter... its a great plant, however it got there though.
8 Jul, 2012
I'd like the birds to drop something like that into my garden :-)
8 Jul, 2012
Previous question
It's a Hibiscus of some variety, a hardy tree like shrub.
4 Jul, 2012