Pansies are short-lived evergreen perennials that are grown in St. Louis as cool weather annuals or biennials. Grow as biennials by planting in fall, mulching in winter (e.g., hay or evergreen boughs) and then enjoying the spring bloom until the plants inevitably succumb to summer heat, at which point they should be removed from the garden. Plants do not need mulching in mild St. Louis winters, but may not always survive extremely harsh winters. Small but established plants generally overwinter better than large ones. A main advantage to planting pansies in fall is that they will bloom earlier (late winter to early spring) than spring transplants. Pansies may of course be easily grown as annuals by starting seed indoors in spring 12-14 weeks before last frost date. Unless a particularly unusual variety is desired, however, many gardeners find in easier to purchase plants from nurseries in cell/six packs in spring. Set out plants in early spring. Pansies are best grown in humusy, consistently moist, well-drained soils in full sun to part shade. Best with part afternoon shade in St. Louis where gardeners like to coax as much bloom as possible from the plants before the onset of hot summer weather. Deadhead spent flowers to prolong bloom. Cut back leggy plants to revitalize. Pansies are the top-selling winter bedding plant in the deep South where they are planted in fall for bloom throughout the winter and early spring.
Pansies are one of the most popular bedding plants for cool weather. Pansies sold in commerce as P. x wittrockiana are mostly F1 hybrids that grow to 8” tall with 2-4” diameter flattened face-like flowers. Flowers come in a wide variety of colors including various shades of blue, purple, red, rose, yellow, apricot, brown-red, white and bicolors, often with contrasting blotching or central whiskering/markings. Ovate to elliptic medium to dark green leaves (to 1.5” long).