Wallflowers.....

There are 2 types of wallflower....biennial (Erysimum cheiri) and perennial. The perennial kind have a much woodier stem and flower beautifully, just cut off the long flowering stem back to a leaf when the flowers have finished.

Thanks for your help, everyone. I think I'll try to grow some from seed so I'll have some for next year.

As far as I am aware wallflowers are bi-annual, you have to sow them now to flower next spring.

You could perhaps leave some to see if they will produce seed. Then gather the seed and re-sow next year. I've never done this with wallflowers but I've done it with other annuals. I'd be interested to hear whether it works with wallflowers.
Also, will they grow in fairly acid soil? Do deer eat them? These two things are the parameters for my flower gardening!!!

Well if they are annual wallflowrs they wont grow next year I have them everyyear but not sure if you can keep them alwys buy new ones to plant in the autumn .
There are some perrenial wllfkowrs and if you have these then yes they
should be cut back once finished flowering.
Hpwe this helps