Help with identifying this rapidly growing plant

I would be very grateful in identifying this plant. This is planted a few years ago by our neighbour and it is spreading into our garden. It appears as if the root is spreading underground and new shoots growing up from the ground around. They said it is some kind of lemon brought from a garden centre.

Does it do anything else? Flower? fruit? I wouldn't expect lemons

Figrat, persicaria is a good suggestion. Vietnamese Coriander Persicaria odorata is sometimes known as lemon myrtle. It is also called Polygonum odoratum. It has inconspicuous pale yellow to white flowers and a slightly lemony smell. However, it does have brown marks on the leaves, which I can't see in the photo. 

I've been looking at some images and all the persicarias seem to have alternate leaves This has opposite leaves. 

it is not a persicaria odorata, because have no red stalk (stem). The asian persicaria we eat at salat or cooking in vegetable soup. I'll looking also for the correct kind, have no idea at the moment...

I think it's persicaria orientalis like this.

Thanks very  much. I have never seen it with flowers, and I could not find any seeds when I checked today. It is a acts like a climber and it grows around and tries to completely cover a other shrubs around. I am posting one more photo with the arrow pointing toward the stems; thicker older stems and new green branches.

Isn't Persicaria orientalis an annual? This doesn't look like an annual.

Yes, but I thing, the thick "wooden" stem stand for some years. Any gardener save seeds for growing in the next year and another say, that P.o. is a self sowing plant, they love the "tree-like" plant. And everybody have own opinion or experience. Greeting, ThaiGer. Look HERE.

Dont think I can help.. sorry

So this is an utterly rampant climber. No flowers, deciduous and it twines. Is that right?

And is growing now at the tail end of winter--and has underground suckers-sounds like a nightmare- is it wanted? 

Gardening Grandma wrote (see)

So this is an utterly rampant climber. No flowers, deciduous and it twines. Is that right?

sotongeoff wrote (see)

And is growing now at the tail end of winter--and has underground suckers-sounds like a nightmare- is it wanted? 

Bring on the glyphosate

When I look at pic#3 , you right, PaulaH. But at the first and sec. pics you can see soft leafes and not varnish/shining...sometimeI think is not the same plant? Or?

Don't know holboellia but googled it and it's taking about 3 leaflets. Can't see anything like that here

There are similarities to honeysuckle, pairs of opposite leaves, and twining anti-clockwise, but I've never seen one like that before