Answer: Biennials usually grow vegetatively the first year and flower the second year so your wallflowers sound like they're right on schedule. If you allow the flowers to remain on the plant they'll produce seeds which you can scatter around the parent plants, or collect and save for sowing next spring. However, if you keep spent flowers cut off the plants, they may behave as perennials rather than biennials.
Wallflower (Erysimum) are perennials or biennials (depending upon species)that grow best in full sun to light shade, in average garden soil, and little to moderate water during the growing season. In your mild-winter climate you can simply trim the dead foliage back, leaving the healthy leaves and stems alone. This will give your wallflowers a jump-start on the spring season and you can expect flowering very early in the spring.
If your plants behave as perennials, you need only to dig and divide the clumps every 4-5 years.
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