This is the time of year when flower gardens start to
look tired. However there are a few plants that love the cooler
temperatures and brighten the fall garden. Chrysanthemums, asters, pansies
and ornamental kale are some popular fall selections.
Ornamental kale, Brassica
oleracea var.
acephala, adds a splash of color during the
fall and early winter. This is one of the few plants that offer color with
foliage rather than flowers. Leaves are produced in a tight rosette and can
be curly, ruffled or featherlike. The outer leaves are typically blue-green
while the centers are brightly colored red, pink, purple, green,
yellow-green or creamy white.
Leaf colors intensify when night temperatures drop
below 60 degrees Fahrenheit. The colors really begin to show with frost and
cold temperatures. It generally takes a few weeks of cool temperatures
before leaves reach their best color. The leaves of ornamental kale will
remain colorful until temperatures drop to 20 degrees Fahrenheit (surviving
to temperatures as low as 5 degrees).
Avoid planting ornamental kale while night
temperatures are still warm. If temperatures are too warm, plants can
become leggy and leaf colors can fade. In addition early plantings are more
prone to pests such as cabbage loopers. After a frost, plants are
relatively pest-free.
Ornamental kale is genetically the same as edible
kale. While it is edible, it doesn’t taste as good as culinary kale
and is best used as a landscape plant. It is from the same genus and
species as broccoli, cabbage, cauliflower and Brussels sprouts but has much
fancier and more colorful foliage. Ornamental kale plants were developed by
selecting kale plants with unique foliage color.
While considered an annual, ornamental kale is
botanically a biennial. This means that it produces foliage the first year
and flowers the second year. Most valued for its foliage, ornamental kale
is grown as an annual.
Most garden centers offer selections of ornamental
kale. To maximize their lifespan look for plants that aren’t
root-bound or overgrowing their container. Root-bound plants will not
enlarge in size even when planted into the garden.
There are many color combinations of ornamental kale.
If you can’t find the selection that you are looking for, it is
possible to start it from seed. Sow seeds in late July to early August,
about six to ten weeks before the average first frost. It’s too late
to plant seed this year, but you can make plans for next year.
Sometimes ornamental kale is sold as ornamental
cabbage or flowering kale. This is not really correct. Ornamental cabbage
has broad smooth leaves and will form a head. Flowering kale is also a
misnomer since the plant is grown for its foliage, not its flower.
Ornamental kale is a great plant to replace fading
annual flowers. Be sure to place them in a full sun location where you can
enjoy the colorful centers. They look best placed in the front of a garden.
They blend nicely with ornamental grasses, sedums and other fall blooming
perennials. Ornamental kale also looks great in container plantings.
Jennifer Fishburn is a horticulture educator with the
University of Illinois Extension Sangamon-Menard Unit. Contact her at
fishburn@uiuc.edu.
This article appears in Sep 18-24, 2008.
