I would buy a few plants and they will spread and the runners will quickly take root. You will then be able to detach the rooted cuttings. I would say that will be quicker than starting from seed. If you need to get 100 plants quickly then you might be able to source some 'liners' (small rooted plants) from a large wholesale nursery and grow them on.

Be very careful I had some and it spread like wildfire had great difficulty digging it out and getting rid of it.

Thank you I have a very long sreep 5ft high embankment to cover, and like most gargeners am in a hurry for it to look nice (and avoid the weedeing)