Plant Cool Season Color During Fall

Robert J. Souvestre  |  12/21/2011 1:09:32 AM

Columbine “Swan Blue white” – Bicolored columbines grace landscapes in April with their stately flower stalks arising above the plant foliage.

Nicotiana “Perfume Deep Purple” adds both fragrance and color to containers and landscapes. Plant in sun for best performance.

Garden retailers are well stocked with cool season annual color and now is the time to plant your landscape! By planting this month and into early November, bedding plants will establish a nice root system and put on growth before cold temperatures arrive. The more time the plant can grow this fall will mean a bigger plant and more flowers next spring.

We are fortunate to have what many consider to be mild winters. Seldom do temperatures drop below freezing for sustained periods and most of the cool season annuals can successfully pull through a cold winter with only a few maybe showing signs of cold injury. A strong, healthy plant that is well mulched will almost always survive and perform admirably the following spring. There are exceptions and calendulas will likely not survive a serious cold snap and petunia foliage will get injured. But that is the price one pays for a potentially glorious color display next spring.

There is much to select from in the way of annual flowers for planting during the cool season of the year. Most of us know about pansies, snapdragons, petunias, garden mums, and older varieties of dianthus, but there is much more.

Violas are the cousins of pansies and continue to gain in popularity. The Sorbet series of violas always perform well in LSU AgCenter landscape plant evaluations. The series blooms early and performs well from mid fall through May. Try these great alternatives to pansies. They should be planted in mass for a great flower show. The blooms will last two weeks longer into the late spring.

Nicotianas are good alternative, cool-season bedding plants for south Louisiana. Nicotiana is flowering tobacco. Most of these for landscape use are “dwarf” in size but still reach heights of 24 inches. Nicotianas have less cold hardiness than some other cool-season flowers, so that needs to be considered. In south Louisiana, they should be able to withstand winter temperature conditions as long as plants are hardened off some before the first frosts and freezes. You also can plant them in mid- to late February. Plants will last until late spring. Flower colors available include white, lime, rose, red and more. They do best during the cool season in a full sun planting, but will perform better into late spring if partial shade is provided. Popular in the series are Nicki, Perfume and Saratoga.

The best of new dianthus is the Amazon series. These are very prolific flower producers. Flower heads are large and will last until mid-May in south Louisiana. The series also has cut-flower potential. Flower colors available in the Amazon series are Rose Magic, Purple, Cherry and Neon Duo. The Amazon dianthus are Louisiana Super Plants from 2010. The Amazons require full sun for proper plant growth and strong stems.

Camelot foxgloves are new to the market. These are also called digitalis. For best results, plant in the fall, and 2 foot-tall spikes of flowers occur in the spring. Flowers come on 2-3 weeks before the popular Foxy variety and last 2-3 weeks longer. Camelot foxgloves were also Louisiana Super Plants in the fall of 2010. Flowers in the Camelot foxglove are lavender, cream, rose and white, with lavender, cream and rose being the better-performing colors.

We know tall growing delphinium but now there is smaller variety for landscape beds. Diamonds Blue delphinium have intense blue flowers and is a new seed-propagated Delphinium chinensis. This plant is considered a first-year-flowering perennial but should be treated as an annual. Plant in full sun in the fall for great flowering performance from February through May. Space plants 12-14 inches apart. Plants reach a height of 18 inches with a 10- to 12-inch spread. If you want to try a tall grower for cut flower use, try the Guardian series. They are available in lavender, white and blue.

Other cool season bedding plant favorites are pansy, larkspur, calibrachoa, nemesia, diascia, bacopa, sweet alyssum, bluebonnet, hollyhock, ornamental cabbage and kale, snapdragon, columbine, sweet pea, poppy, lobelia, stock and statice.
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