Certain cool-season annuals are sometimes grown as perennials. Can I expect these plants to come back each year?
Certain cool-season annuals, like mums, are also sometimes grown as perennials. Can I expect these plants to come back year after year?
Cool-season annuals are annual plants that prefer cool temperatures, growing best in spring or fall. Many are tolerant of a light frost often surviving down to 28°F or sometimes even 25°F with little damage to flowers or leaves.
Plants such as mums, coral bells, and black-eyed Susan are sometimes grown as perennials, but also grow well when treated as a cool-season annual. These species will not reliably over winter when planted in the fall. Fall planting does not allow sufficient time for root establishment therefore they don’t overwinter well. They are best treated as annuals when planted late in the season. Some species traditionally treated as annuals, like pansy, dianthus, and bachelor’s button, will frequently survive the cold winter temperatures when planted in fall and begin growing and blooming again in early spring. These plants often do not tolerate the warm temperatures of summer, however, often browning and dying in the heat. Because of this, they are not treated as perennials despite being winter hardy most years.
Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Horticulture and Home Pest News, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on . The information contained within may not be the most current and accurate depending on when it is accessed.