To prune or not to prune

They are short lived perennials so you could take cuttings then cut it back a bit and see what happens.

I have had these plants for years, all from cuttings from one original plant.
They are very easy to propagate especially when a semi ripe cutting is taken in mid summer. It should have rooted ready to plant in late summer.

Might be too late for the current one then, but shall try this with its replacement. Thank you.

It is short lived, just a few years, we usually replace with another mature plant, the Bowles Mauve (?) is the best one.

We still have one in flower, it never stopped all through Summer Autumn and Winter!

Mine is several years old, it started off in a pot but is now happier in the garden. It’s quite large and has also flowered throughout the winter.
I might take some cuttings this year.

If wallflowers are grown in the same spot for several years, they can become susceptible to club root. This stunts the growth and can cause the plant to wither back and inhibit new growth. If you can see that the plant is withering from the centre of the plant , outwards, its best to pull it up and burn it. When replanting with a new plant, find a different spot in the garden and don't replant in the diseased area for at least 2 years.