The florists freesias are typically hybrids of F. alba, F. leichtlinii and F. corymbosa. These are very floriferous, highly scented, blousy, but not hardy. There are some species and their forms, which will thrive in a sunny, sheltered part of the garden, or in a pot and moved into the dry position over winter. All hail from the southern half of Africa, with F. laxa, F. grandiflora and the remarkable lime-green flowering F. viridis worth considering. Some of these were previously known as Anomatheca.
Famed for their fragrance, freesias are presumably producing the scent not for us but to attract pollinators. However, ones growing in our gardens seem not to exert any particular attraction to our native insects, and the highly bred, often doubled forms are likely to have less of the resource that insects would be looking for anyway.