What is this weed?

[2ducks2ducklings]

We bought our house, which needs complete renovation, in March. The garden at that time was mainly gravel. Obviously the garden isn't our priority at the minute, but I braved the wilderness last week and it is completely taken over by this weed! What is it and how on earth do you get rid of it? We plan on laying turf where the gravel is/was so my husband is reluctant to douse the place in weedkiller. But it's just so persistent and the roots seem to spread everywhere, it even comes through Tarmac!
Any help or advice will be gratefully received!

Looks like Valerian. Not a weed (unless it's rampaged over everywhere). Am busy cultivating it in a difficult border! Spreads quickly, gives lovely flowers.

Yes Valerian. It also has white flowers sometimes. Bees like it. Lots of it growing wild where I live but it is also cultivated in gardens. Pretty!

So it's not a weed? I assumed it was because weeds are usually all I can keep alive in my garden! They do seem to be 'thriving' though.

Valerian, also called Centranthus ruber. It looks beautiful.

Red valerian, rather than true valerian. We have loads, none of it actually planted - grows like a weed, but it's pretty so it can stay!

It grows through my privet hedge, on the road side and looks lovely.

If Valerian grows well in your garden, then you could also try:

Sedum 'Herbstfreude'
Verbena bonariensis
Crocosmia
Geranium 'Roxanne'

All are pretty low maintenance.