Ornamental kale is becoming increasingly popular with gardeners looking for a cool-season ornamental to compliment pansy plantings. They are at their best in late Fall, and depending on the weather, may look good into the following Spring. Round-leaved types are called ornamental cabbage, while lacy-leaved types are called ornamental kale, but generally we use the generic “ornamental cabbage and kale” as the culture and uses are the same.
According to Gerald Klingaman of the University of Arkansas, “kale” is the Scot’s version of “cole”, the Roman term for the vegetable, which originated in the Mediterranean area. (Giving us the term “cole crop” for the kale/cabbage/broccoli vegetable group, “cole slaw” and so on). It eventually made its way to Japan, where people selected colorfully-leaved plants for ornamental purposes. Ornamental kales were brought to the United States in 1929 as a result of a USDA-sponsored collecting trip to Japan, and they first appeared in US seed catalogues in 1936. Most cultivars sold today were bred in Japan, and there are called “leaf peonies.”
Cool weather is required for good coloration. According to the University of Massachusetts, temperatures below 50 degrees cause the loss of chlorophyll, which allows the underlying purple, pink and white coloration of the leaves to become more prominent. Very cold temperatures in winter or heavy snows will tend to shorten their ornamental life. Some years, they look good into April, while other years they are pretty ratty by Christmas.
They are biennials, which means that they have leaves the first season, then form a flower spike in the spring.The yellow-flowered spike is generally considered to be of minor ornamental value. Ornamental kale and cabbage are quite attractive when planted in autumn mixed containers with pansies and ornamental grasses, or when used en masse in the ground with pansies. Like bulbs, they are less attractive when planted in rows like frilly little soldiers.Ornamental kale is available at our garden centers in early to mid-September, but will be more colorful at the end of the month or in early October. Be sure to watch for it and add it to your fall-color palette!
By Larry Hurley, Perennial Specialist