Light: Violas are tolerant of most conditions, yet will thrive in full sun or part shade especially during the spring, yet will easily fade in full sun during summer heat, and best to transplant into dappled shade.
Soil: Moist, nutrient-rich soil that is well drained and supplemented with compost. Fertilize, as needed, to keep plants strong and healthy.
Primula elatior (this one grown by primrose expert Amy Olmsted in Vermont) as dug from the garden for a primrose exhibition, proves how resilient primroses can be in the spring, as all tolerate being dug and potted for a few days and brought indoors, only later to be returned to the garden often after dividing them (this is usually what most growers do).
https://www.americanmeadows.com/perennials/viola/how-to-grow-viola
http://www.growingwithplants.com/2016/04/the-many-secrets-behind-success-with.html