Our primulas broadly split into two categories. The riotous colour of candelabra primula and similar, which tend to be larger, producing whorls of flowers and many of them. Often very brightly coloured, with oranges, pinks and reds prominent. The second group are our native oxslips, cowslips and primroses, which tend to be low growing and producing yellow or similar flowers. Most prefer dappled shade, or soils which don't completely dry out, although our native primrose will take a drier spot.
Most primulas have a device to enable cross pollination between plants. Flowers on some plants will have the style longer than the stamens (pin), whilst other have the style shorter than the stamens, (thrum). These allows successful pollination to occur only with flowers of different style lengths.