Posted: 10/10/2015 at 11:43
I've just enlarged the pic - should've done that in the first place - and it's definitely a wallflower. It could be the bedding type which is usually grown as a biennial thought it's actually a short-lived perennial. I've kept them growing for 3 years and they can grow into an amazing bush before they just peter out.
If it flowers only in spring, it's a bedder. If it flowers all summer, it's Erysimum. They don't live that long either, I think because they flower themselves to death. My Bowles Mauve has flowered non-stop, including winter, for four years now. I keep thinking it's finished, give it a trim and back it comes.
I've also found that there are buds left on leggy flowery stalks that do well in a bottle of water tucked among other plants. I often use cut flowers in the garden. Then you can have sun-loving flowers in shady places.