Being a paint that is resistant over time, the varnishing step is not mandatory. However, it can bring a little extra to the final rendering on the cherry blossoms. If you choose a matte varnish, the creation will appear more natural while with a glossy varnish, the colors will be more eye-catching.
To apply the varnish, you need a completely clean brush, dip it in the varnish and spread it on your drawing in thin layers. 1 to 2 layers are enough then let dry for 24 hours.