I've grown it, but I didn't like it much, so it was one herb that Had to Go when I moved to this place with it's dining-table-sized garden. I found it too spiky for comfort! But it did well here in the subtropics - I kept it in a pot, so it never became a nuisance. Here's the information I have on growing it, which I hope will be helpful.

Tropical perennial, sometimes treated as an annual in cooler areas. Pungent leaves have toothed margins and they grow in a basal rosette pattern. They can reach 25cm long, with sharp spines along the leaf edge. White flowers are followed by a round fruit covered with rounded protrusions. Sharp spines also occur on the flower stalk. It has a taproot which grows down to about 12cm. Also known by many other names including Mexican Coriander, Culantro, Recao, Long Coriander, Perennial Coriander, False Coriander, Ngo gai, Spirit Weed, Fitweed.

Cultivation: Propagate by seeds, sown in spring. They can be slow to germinate, often more than 21 days, and are best given bottom heat around 24C. Keep the soil moist but not wet while germinating, and use a deeper tray than usual to accommodate the tap root. Transplant about 8 weeks after the seedlings emerge. Occasionally propagated by root cuttings taken in early spring, but the plant does not tolerate root disturbance well. Grows best in moist, shaded positions with good drainage. It can survive in poor soils, but it is best to feed frequently with high-nitrogen fertiliser to keep the leaves soft. Does not tolerate frost. Cut off the flower stalks frequently to ensure continuing production of new leave. May be planted indoors in cold areas.

This is one herb I've never had a problem with - it seems to survive drought and winter temperatures quite well in my garden.

Thanks Daisy, I realise it can be a bit spiky but if it's grown quick and lush it can be much softer. I've bought bunches from the asian grocers which have been broad flat soft leaves like dandelion leaves.

Andy - where are you? What is your soil like there and what position have you got your long coriander in?

I'm not growing it in any special position or soil - just in my herb bed amongst the Mediterranean herbs. It doesn't grow prolifically, but has survived for three years now. Maybe I'm just lucky.
I do pull of the flower heads, though.