Solved Any Idea what this plant is

This is my first post since Gardeners World forum closed down.
Can anyone help to identify this plant in my garden.
It is 3ft tall with downy but hard stem. But very distinct
red areas on the stem where a shoot comes from. I am worried
that it may be J Knotweed or H Balsam.
It seems to be growing among a lot of Lupins I purchased on-line from a very reputable company.
Any help would be appreciated.

 

Could it be Evening Primrose?

 

It definitely isn't Japanese Knotweed or Himalayan Balsam.

 

Agree, neither JKW or HB.

 

Maybe send the company a photo and ask if they want it back?

 

It looks rose bay willow herby

 

Could be Rosebay Willowherb, true. Here's a check you can do - I copied the following from wildfooduk.com:

Leaves. Long and lanceolate, green sometimes with a flush of red or a red leaf base. The leaves of Rosebay Willowherb are unique in that the veins are circular and do not terminate at the leaf edges but form circular loops and join together. This can help with identification before the flowers appear.

 

I can't tell what it is but this plants is one of the weed collection in front of our house (together with many other weeds). It's one of those that once left, they happily expand their territory.

 

It could be willow herb - that was my first thought, but the pic isn't good enough to be sure. There are several types, and many do have red on the stems.
It could also be loosestrife, which is quite similar - are those buds at the foot of the pic part of the plant?
Definitely not JKW or H. balsam, as others have said.

 

I'm another vote for a willow herb thingy.

 

A good description @NigelJ - and the correct horticultural term!

I hate the stuff - I have a less polite term for it...

 

I have unfond memories of biology field trips and recording plants in a series of squares across sand dunes and recording nothing but Rosebay Willow Herb, Marram grass or Sea Buckthorn. Retrieving the wire square from the Sea Buckthorn has no good points.

 

I can imagine that would be a painful experience @NigelJ .
The edges of those seaa grasses are sharp too.

 

I call it the Railway Weed. It comes up everywhere here. I think oh look what's this nice plant coming up and then when it's quite big I remember and yank it up. It pulls out quite easily.

 

Thanks everyone. I will do some more investigating and let you all know.