Taking an environmentally sensitive approach to pest management


Missouri Environment & Garden


David Trinklein
University of Missouri
Plant Science & Technology
(573) 882-9631

Pansy: Always in Bloom Somewhere

David Trinklein
University of Missouri
(573) 882-9631

Published: September 24, 2012

As you read this article, somewhere in North America pansies are blooming prolifically in a garden, much to the enjoyment of those observing them. That same statement truthfully can be made any month of the year. This delightful garden plant flourishes in the winter in the far South and in the summer in the North. Spring and fall are the times of the year that we Midwesterners are able to enjoy their unique color and delicate fragrance. If ever there was a plant that deserved the title of “the flower for all seasons” it is pansy, and September is an ideal month to plant them in Missouri for color that will extend for many weeks to come.

Pansy is a member of the Violacea family and carries the scientific name of Viola x Wittrockiana. The latter indicates it is a hybrid and a close relative of viola, a flower with which it is often confused. Both species have flowers consisting of five petals; a trait which is quite typical for most dicots. However, pansy has four petals pointing upward and one pointing down whereas viola has three pointing upward and two pointing down. Additionally, violas usually bear somewhat smaller flowers than do pansies.

The history of pansy is closely linked with its ancestor the viola. Violas are thought to be endemic to the cooler regions of Europe and were cultivated by the Greeks as early as the fourth century B.C. Their initial use primarily was for medicinal purposes. Some while later, a watchful gardener noticed a particular viola that flourished in alpine meadows blessed with abundant sunshine. This strain of viola was given the common name of wild pansy. One might speculate the observant gardener was from France, since the word pansy can be traced back to the French word pense, which means “thought” or “remembrance”.

European gardeners prized both violas and wild pansies and grew them in abundance. It was in the 1800’s that an English nobleman by the name of Lord Gambier and his gardener, William Thompson, began crossing various species of the genus Viola. These crosses resulted in flowers of unusual colors and color combinations as well as increased flower size. History credits William Thompson, the gardener, with making the cross that resulted in the new (and now familiar) species Viola x Wittrockiana. This particular cross produced flowers with huge blocks of color (or faces) on the lower petals. The flowers of many previous crosses possessed only lines of contrasting color.

By the mid 1800’s pansy breeding was being carried out in many European countries including England, Scotland and Switzerland. These breeding efforts resulted in the development of hybrids with greater plant vigor and flowers that had no dark blocks or lines. Thus, “clear” pansies got their start in the horticultural world.

Pansy was welcomed to North America by gardeners and its popularity soon skyrocketed. A 19th century seed catalog described pansy as "The most popular of all flowers grown from seed--our sales exceeding one hundred thousand packets a year." That was a remarkable statistic, considering the early date and the population of the United States at that time.

Over the past several decades pansy breeding has been carried out in a number of additional countries including the United States, Germany and Japan. These efforts have produced pansies with new colors, including new shades of pink, rose or orange, as well as flowers with unusual bicolor designs. Given the current popularity enjoyed by pansy, the improvement of this charming little plant is far from over.

Most gardeners choose to plant pansies that have been started by commercial greenhouses and are sold in bedding plant “packs”. Choose plants that are “stocky” with healthy leaves and free from pests. Plants with several un-open buds are preferable to those whose flowers are all fully matured and likely will result in a greater display of color sooner.

Pansies enjoy cool temperatures and abundant sunshine. Unfortunately for pansy lovers, this combination of environmental conditions is available only in the spring and fall in the Midwest. To extend the useful life of pansy in the spring or to get an earlier start on fall color, an exposure of morning sun followed by afternoon shade can be chosen. Although pansy should be considered an annual in Missouri, fall-planted pansies frequently survive our winters and produce color in the late winter or very early spring after temperatures begin to moderate.

Given the very fine and delicate nature of the root system of pansies, the soil in which they are planted should be porous and highly enriched with organic matter. The latter promotes good soil aeration along with adequate water retention. Incorporating three to four inches of well-decomposed organic matter is a “best management practice” for preparing most soils for the production of annual flowers, including pansies. Additional pre-plant fertilizer may or may not be required depending upon the inherent fertility of the soil.

When planting, space pansies about six to ten inches apart and water well, directing the water to the base of the plant. Pansies should never be allowed to dry and, in most settings, require between one and two inches of water weekly. Additional fertilizer can be supplied in water soluble form, if required.

Pansies are relatively disease and pest free. Yellow leaves often indicate the presence of root rot which, most often, is caused by over-watering. A white, powdery substance on the leaves (and stems) is indicative of powdery mildew. Choosing a location with good air circulation can help to prevent the latter. In both cases, prevention is the best “cure” for plant diseases.

Insect pests include aphids and spider mites. Like pansies, aphids also thrive in cool weather and can build up large populations rapidly. Start with insect-free transplants and check regularly for aphid infestation. The latter will most likely appear on the tips of leaves and flowers and, left unchecked, may result in stunted growth and reduced flower production.

Spider mites are more likely to attack fall plantings of pansies than spring-planted due to the affinity of the pest for warmer temperatures. Leaves that looked “stippled” and begin to turn yellow are symptoms of spider mite damage. If either of the two pests should occur, choose pesticides that have low mammalian toxicity and are environmentally friendly. Read and follow label direction when applying any pesticide.

Pansies occasionally will be attacked by slugs and/or snails. These pests produce gaping holes in the leaves of a plant. Since both are nocturnal in their feeding habit, feeding damage is the easiest way to determine their presence. Control of both slugs and snails can be fairly easily accomplished with poisonous baits.

Many avid gardeners become a bit depressed in the fall as they contemplate the end of the growing season. Pansies help to extend that growing season because of their ability to withstand sub-freezing temperatures. Therefore it might be concluded that pansies are as therapeutic for our inner being as they are beautiful to our eyes.

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REVISED: July 31, 2012