Once they have finished flowering you can then divide the little rosetts of plants that form by the side of the mother plant.
Make sure you keep them well watered after planting.
You can also sow the seed of some primulas and take root cuttings too.

Hi Louise re primulas etc. they are all the same 'family' i.e. Primulacea but they are different genus.

With apologies to Moon Grower, Primroses, Polyanthus, and Cowslips are all members of the genus Primula, though depending on which particular plants you are thinking of, they are probably different species or hybrids. The Primrose Family (Primulaceae) covers a much wider territory, including Rock Jasmine, Shooting Star, Brookweed, Snowbells, and many other plants.

Louise, if you have a large clump and you find it difficult to sort out which roots belong to which rosette of leaves, soak them in a bucket till the soil's all off, then separate them and replant, obviously keeping them well watered afterwards.

thanks everyone for your help.

bamboo- i'm assuming i dig up the whole clump to do this?

Yes, of course. They won't mind, I've done it loads of times, they grow away very quickly once separated.

thanks x

Thanks, 2 years after being asked this has helped me :) off to do some digging :)

Glad it helped Magna!

I now have 6 primulas, was a 2 or 3 year old bring n buy sale plant.... Here's hoping they take! Will put some pix up tomorrow x