The butterflies that have been hibernating over the winter months & will now be flying around are:
Small Tortoiseshell, Red Admiral, Peacock, Comma, Brimstone
I have seen only these 5 species in March.
There's a reasonable chance of seeing
Holly Blue, Painted Lady, Small White, Speckled Wood
Other garden-visiting butterflies that possibly might be seen in this month are:
Clouded Yellow, Green-veined White, Large White, Orange Tip, Small Copper, Wall
The butterfly-attracting plants that I've seen butterflies visiting in March are:
Grape Hyacinths (Muscari)
Forget-me-nots
Dandelions
I've also produced an overview of the butterfly year and there's a list of butterflies flying each month on my calendar page.