Not very many Prairie gardeners are familiar with flowering cabbage and so inclusion of some of these plants may add an element of surprise to your garden and provide an interesting experiment. Flowering cabbage and kale, ornamental cabbage and kale, and decorative cabbage and kale are all terms that refer to the same plants, although the cabbages generally have smooth leaf edges while the kales are fringed. They are all hybrids in the Brassica (Latin for cabbage) family and the last word in their Latin name, Brassica oleracea, means vegetable-like. They are indeed similar in many ways to the other members of the cabbage family such as cabbage itself, broccoli and cauliflower.
Kales come in two different forms: fringed-leaved varieties whose leaves are fringed and ruffled; and feather-leaved forms whose leaf edges are finely serrated and deeply notched. All flowering cabbages and kales produce coloured leaves which are very decorative – the term “flowering” is a misnomer as the colour comes from the leaves rather than from petals of flowers. They are edible, but much inferior to culinary varieties.
Decorative kales and cabbages take about three months from seed to produce colourful heads so they are usually purchased as individual plants at a greenhouse. They are quite difficult to grow from seed started early in the house because they demand low temperatures and bright light. If not given the required growing conditions when they are small, the plants will develop elongated stems, and they must not have their roots restricted and so must be grown in large individual pots, which is difficult to accommodate indoors.
Ornamental cabbages and kales may not exhibit strong colour early in the season because low temperatures consistently below 20 C are required to cause the plants to lose chlorophyll and reveal their colouration, which ranges from white to pink to red purple. In our area this usually doesn’t happen until late August and takes a couple of weeks to occur. Once nighttime temperatures drop below 20 C the process will begin.
The pests and diseases that plague the rest of the Brassica family also attack decorative cabbage and kale. Flea beetles and cabbage worms are the most destructive since they attack the foliage, which is the reason for growing the plants in the first place. Since the plants are often located in an area where their beauty can be appreciated, visible barriers or insecticides which are very obvious, such as potato dust, are not suitable options for deterring these pests. Luckily, because the plants are not going to be eaten, a liquid insecticide such as malethion can be sprayed on the plants to control insects.
Ornamental cabbages and kales look good in rows used to edge planting areas, dotted here and there in a mixed border, or added to a mixed planting in a large container. They add a unique touch to any landscape and are well worth including in your garden.
– Albert Parsons writes from Minnedosa, Manitoba