The first looks a little like Leycesteria formosana. It has hollow stems (seen in the dead stems). The small amount of foliage I can see has the slightly reddish edges seen in this plant. The foliage is also presumably opposite as the branches are.

The second has the look of a Forsythia.

The third is a Willowherb (Epilobium), not exactly sure of the species, possibly American Willowherb.

The 3rd is a weed and needs removing asap!

Thanks Fractal but I think second one is not Forsythia. I will try to get a better picture next time.

Moon grower, thanks for the advice. I will kill that weed asap. I liked the small flower though. Is there a name for this kind of weed?

As Fractal said it is a Willowherb (Epilobium) spread like wildfire.

Thanks again.

@Moon_grower @Fractal is there any cure for American willowherb as I keep throwing these plants away but they are back sooner or later within a week. Is there a permanent cure?

Nope, weed, weed, weed and weed some more...

Thanks Moon_grower

xxx