Wallflowers (Cheiranthus cheiri) form clusters of yellow, orange or maroon flowers atop 12 to 30 inch stalks. They bloom profusely from spring until fall, though flowering may decline in midsummer as the temperature becomes warmer. Wallflowers attract butterflies and bees to garden beds and are often planted in larger butterfly gardens. A short-lived perennial, the wallflower is grown as an annual in most locations. The plants readily self-seed in the garden bed once they become established.
Add a 2-inch layer of compost on top a full sun garden bed in spring when the soil thaws out and dries enough to work. Till the compost into the top 6 inches of soil. If mud clings to the tiller, the soil is still too wet to plant.
Sow wallflower seeds 6 inches apart. Plant the seeds ¼ inch deep and cover lightly with soil. Wallflower seeds germinate within three weeks in cool but not frozen soils.
Water the bed to keep it moist, if necessary. Spring soil retains moisture well and may not require irrigation during the germination period.
Thin the plants once the seedlings are 2 to 3 inches tall. Pluck out the excess seedlings so the remaining plants are spaced 12 to 18 inches apart in all directions.
Wallflowers prefer soil that remains moist but doesn't become soggy. The plants rarely thrive in poorly draining beds. A native of Britain, the wallflower earns its name because it grows wild from the sides of cliffs and stone walls in its natural habitat.
Wallflowers are mildly toxic and should not be ingested.