Violas are an early blooming plant. These perennials are often grown as an annual. Most people believe they are annuals. They are early bloomers in late spring to early summer. Then, shrivel in the mid summer heat.

They are native to the southern hemisphere. Easy to grow, you will often find Violas growing in the wild, in their native regions.

There are so many different types of primulas, it’s difficult to choose which ones to go for. There are taller varieties such as the lollipop-shaped flowers of Primula denticulata, which come out a bit later, or the traditional, more familiar types such as the primrose and the cowslip.

They are really easy to grow, flourishing in virtually any situation provided they are planted in rich soil, although cowslips favour free-draining soil and the Asiatic types provide a riot of colour in heavy soil.

http://www.gardenersnet.com/flower/viola.htm
https://www.irishexaminer.com/breakingnews/lifestyle/our-guide-to-growing-perfect-primulas-and-how-to-make-the-most-of-these-colourful-plants-833222.html