Amy Brothers — Cold-tolerant annuals can be planted now to give your garden a boost of flowers and color that will last late into the fall. These “companion plantings” are an excellent addition because little else in the garden is blooming.
Annual flowers allow gardeners the means to experiment with relatively inexpensive plants on a seasonal basis. If a new design is desired, gardeners simply can plan the changes for the next growing season. These annuals are unsurpassed for adding flowering color to beds or borders, in pots or containers on the patio or deck. They also may be used for cut flowers, in rock gardens, window boxes, hanging baskets, screens or as temporary fillers and ground covers.
Annual versus perennial
The term annual refers to plants that are grown for only one season. You usually plant seeds in spring or summer, or purchase plants started in a greenhouse. A true annual completes its life cycle in one growing season and then dies. Because their primary concern is to complete the reproduction process, annuals bloom for an extended period of time trying to produce as much seed as possible before dying. This extended bloom time makes them an excellent addition to your landscape. With the right planting schedule, annuals can provide nearly year-round color.
Annuals differ from perennials, however, because perennials complete the reproduction cycle year after year so they are more likely to bloom for only a short period of time. Perennials grow back from the roots or stems each year. Perennials vary in winter hardiness because many have minimum temperatures that they can survive.
Perennials in the Southern United States may not be hardy enough to survive the winter in a Northern state. Some of the ornamentals we plant in Oklahoma are used like annuals but they actually are perennials not adapted to survive our harsh winters. Other perennials may display low or erratic winter survival rates such as dianthus, dusty miller and mealy cup sage. Thus, they are generally not dependable as perennials in Oklahoma’s conditions.
This is why some of your “annuals” you planted last summer may emerge the next spring healthy and full of life after a mild winter. Or sometimes seeds produced by annuals will sprout and grow the following year.
Annuals also have different levels of heat and cold tolerance. Some of the cold-tolerant plants that are outstanding for fall planting include:
n Ornamental Cabbage.
n Dusty Miller.
n Ornamental Kale.
n Pansy.
n Snapdragon.
Annuals typically are used in flower beds or as borders to enhance a perennial garden. In smaller beds, annuals may constitute the entire planting, whereas in borders they add continuous color at or near the front of the bed, which may contain perennials, ornamental grasses or even woody ornamentals. Annuals fill bare spaces and add color to dull areas. For example, when spring-flowering bulbs cannot be removed, annuals can be inter-planted for cover after the bulbs.
So, if you are not quite ready to give up your garden for the year, fall annual plants are an excellent way to hang on to your summer passion a little longer. Be sure to analyze light levels in areas to be planted so you can purchase plants adapted to either sun or shade. Removing spent flowers — known as deadheading — helps the floral display to appear more attractive and can stimulate a greater number of blooms.
(Amy Brothers is a horticulture educator for the Oklahoma County OSU Extension Service.)
