I could be quite wrong...but I think of these primulas as a much more northern plant than even my z7.

I wouldn't equate hardiness zones with either a northerly or southerly orientation :-) There is really no substance to that assumption!

But to to answer the OP, I don't see why you couldn't grow these in your location. They are a common winter bedding plant a Southern California zone 10. In milder zones they are definitely a cool season performer, blooming in winter and into early spring. I would probably want to time seed starting to coincide with the plants being large enough to be planted out in mid to late fall.

Well the question of growing them as an annual is quite different than as a persisten perennial (which was my thought).

Oh, they are quite capable as being perennial that climate! ( a great many common bedding plants are only 'annual' in colder climates). It is just that they tend to be sold as seasonal color, in much the same way chrysanthemums are in fall.

However for them to be perennial in z10, I would avoid a full sun location and make sure the planting area soils stayed evenly moist. And I'm not sure how much they will tolerate summer humidity either, but SoCal has none and I doubt Malta has much.

Yeah, those things just melt by June here...with our humidity and temperatures.

I’m in zone 10 and have primroses. I buy them in 6-packs - never tried starting from seed. They are a winter bloomer for me. Some survive and come back the next year when the rains start.

I think it's a bit late to start sowing them now, but do you think if I sow them in September for exple, they'll be ok ? The autumn in my area is very mild, but temperatures rarely drops below 19 degrees celsius in Autumn

I grow quite a lot of common European primrose (vulgaris, vieris, elatior, auricula - nothing too tricky and good for a Mediterranean climate, unlike the trickier Asiatics. I save a lot of seeds...and treat these very differently to seeds which have fallen into dormancy. Once they have turned brown, they are a bit slower than seeds which are sown while green...but just as reliable. I sow them on the surface of a gritty loam, in 4 inch pots, topdressed with chicken grit. They do need a rime of stratification, so you might have to use the Deno method in a fridge (I can leave mine in the cold greenhouse all winter). They usually sprout at any time between January to April (cowslips were my first up this year)

I have not grown polyanthus but do grow auriculas which have a similar floral architecture. There are many primula grown for spring bedding which are, at least for me, very far removed from our pale yellow primroses but horses for courses..