Solved Mystery plant - wild flower perhaps?

This has popped up in my garden, growing near the base of a hedge and I've no idea what it is. I'm thinking possibly a native wild plant but what is it?

It's about 2-2½ feet tall (60-75cm), the leaves are up to 6ins (15cm) long at their largest. The flowers are tiny, green in colour and born on racemes which are 4-5 ins in length. The individual flowers are no more than 3 or 4mm in diameter. Neither the leaves or flowers have any scent which I can detect.

Any suggestions?

 

Not a native that I recognise

 

Could it be ragweed, if it is don't thank me I've run it through an app on my phone, not 100% but quite useful.

 

I think it looks very similar to ragweed

 

Thanks for that @mazambo and @Tetters It's definitely Ragweed. Not a native so that's probably why I didn't recognize it. Often turns up in bird seed apparently and produces lots of pollen so can cause autumn hay fever.
Wondered why I had a sneezing fit out in the garden yesterday!

Apparently the seeds are very popular with birds so I'll probably leave it there for a while.

 

It is one of the worst plants for causing hay fever, and can create havoc for some poor souls. Evidently it produces huge amounts of pollen.

 

Trunky...any chance of more pics to show the flower buds fully open.

 

I agree, Common Ragweed. Ambrosa 'Artemisiifolia'

 

Ambrosia artemisiifolia......Thanks Sheal...and Trunky.
Most interesting.
Never come across this plant before.
Seems to be an alien invader to UK.

Quote wiki....."Ambrosia artemisiifolia, with the common names common ragweed, annual ragweed, and low ragweed, is a species of the genus Ambrosia native to regions of the Americas.
Invasive species
Common ragweed, Ambrosia artemisiifolia, is a widespread invasive species, and can become a noxious weed, that has naturalized in: Europe; "


Ragweed, Ambrosia artemisiifolia - GB non-native species secretariat

Seems to have small round tiny flowers which are male.

File:Ambrosia artemisiifolia male flowers.jpg - Wikimedia Commons

And also female flowers.


ambrosia artemisiifolia female flowers - Google Search:

 

We never stop learning do we Silver Surfer? But as I'm getting older remembering the names is a nightmare!

 

I remember encountering loads of posters in France years ago warning about the dangers of ragweed, which was spreading there. Very nasty stuff for those sensitive to it.

 

I think you're confusing Ragweed with Ragwort @Cinnamon, they are two different plants.

 

Ragwort is harmful to animals,especially horses.