English wallflower is a charming little plant with cheerful yellow, orange or red flowers. While English wallflower is a perennial if grown in zones 4 through 6, it is grown as an annual or biennial in most cases. English wallflower thrives in cool climates and can tolerate a variety of soil types, but if you live in a cold climate and want to see blooms next year it is best to winterize English wallflower. Winter protection for English wallflower is on par with other perennials.
Cut the amount of water you give your English wallflower in half. English wallflower can handle moist to dry soils, but it is best to leave the soil dry during the winter so as not to freeze out the roots.
Prune all the remaining flowers off of your English wallflower. If their is any fruit on the plant, it can be removed or left for the birds to eat. Trim back any dead or damaged stems to the base of the plant. Leave the rest of the foliage alone.
Cover the ground around your English wallflower with a thick layer of hay or pine needle mulch. This will keep the ground warm for the roots of the English wallflower. Mulch after the first frost.
Allow any remaining leaves on your English wallflower to turn brown and die back. They can be removed if you desire. Do not cut off any of the die back until the spring. The die back helps protect the English wallflower from further die back.
Mulch over the top of your English wallflower once the ground is frozen with a thick layer of hay or pine needles. Make sure the mulch is 3 to 4 inches thick.
Stop watering your English wallflower once the ground is frozen. Do not water your English wallflower again until the ground thaws. If you do try to water it, the water won't be able to penetrate the soil and it will just freeze.