Mallow

Sorry - no.

I love mallow but it caused a brick wall in the garage to crack because we didn't give it enough water!

Is it the wild mallow? If so my gardening magazine for this weeks says you can make a tisane with the flowers - good for the digestion:
www.bio-enligne.com/alimentation/tisanes/mauve-bio.html
And it seems to be very tough, don't worry about cutting it back.Isn't Lavatera similar? That's tough too, doesn't mind pruning.

DH has spent most of the morning ripping out a load of mallow which has self seeded in one of the flower borders. It has a nice 'wild' look but is a bit of a thug in our garden.

I cut the individual bobbles of seed off. But I am trying to establish a cottage garden, so I won't mind if some self seed.

I have the shrub form and once it starts flowering it flowers well into the autumn. I cut it right back every spring and it regrows from the base.

I cut it back to the ground at the end of summer. It comes back beautifully fresh each year.

I was hoping that taking the dead flowers of would encourage more flowers, but I am unsure whether to take the whole stem of dead flowers off or just the individual seed heads and leave the stem.

Don't get mad at me if it doesn't work - but I would cut the flower stems back to the last group of leaves. Then add some liquid fertiliser when watering to encourage new growth.
If you have more than one plant try one that way and the other just deadheading, as an experiment.
I have a similar problem with a patio rose that husband bought. After it finished flowering I cut the main stems back, but left one just deadheaded. That one has produced new growth first, the others just starting, so the plant has lost its shape.