Once they have died down cut them down to 2"-3" above ground level.

http://www.thegardenersalmanac.co.uk/Data/Althaea/Althaea.htm

Edit; Incidently are they an annual or perennial variety?

I'm not sure, I planted them last year but they didn't flower till this year, if that helps. I hope they are perennial though...(they look a bit rough at the moment and some of the buds are still there but not coming out, as though they died before they had finished flowering)...thankyou by the way

This seems ok to me as I find I dont get proper flowers on mine for 2-3 years. I dont cut mine down after flowering I leave and collect the seed once the pod has dried and turned brown. Some do come back year after year I have one that has flowered for over 12 years now, despite having rust.

Thankyou, that sounds promising...although I did just look up 'Unwins seeds', where I bought them and they didn't come under 'perennials'....

Thats the reason I asked my perennials are 6-8 ft high!

Yours didn't look that high!

Hollyhock are considered biennials or short-lived perennials. All mine are very tall, and as long as they get a cold snap they should reseed and continue for years.

they do re-seed - usually in the wrong place. Here they grow on the path (road) to my house it helps my driving skills to try and avoid them! they do get rust no matter what you do (usually on the lower leaves, so if they end up in the back of border where they're masked by smaller plants this is good) they turn up in all sorts of colours but here we have the pale ones (pink, dark pink, yellow, white). I still yearn for burgundy but nature hasn't done this for me yet!...

Thankyou very much all!