Q. The ornamental kale in my flowerbed developed small yellow flowers this past December. I’ve never seen it do that before. Any idea why this happened?
A. So-called flowering kale and flowering cabbage are ornamental types of the edible crops, grown for their colorful foliage.
Cabbage and kale have a biennial growth habit, producing foliage only the first growing season, then flowering and setting seed the second growing season. Both the ornamental and edible types are grown as annuals in Indiana. The plants are usually killed by winter’s low temperatures before they have a chance to flower. Last fall, however, we received enough cold weather to satisfy the chilling requirements needed to initiate flowering (called vernalization), yet not cold enough to kill the plants. I took these photos in the Purdue Horticulture Gardens in West Lafayette, Ind., on Dec. 19, 2013. Note the elongation of the flowering stem compared to the adjacent, still-rounded heads on the specimens not yet flowering.
Flowering cabbage flowers
Flowering cabbage flowers and foliage
Flowering cabbage foliage