The Johnny Jump Up, botanically known as Viola tricolor, is a small, cheerfully colored plant often grown as an annual or biennial. Its three-colored flowers bring early and extended color to gardens and containers. This plant spreads widely through self-seeding, not through creeping roots or runners. Gardeners should know that this species will “jump up” in new locations throughout the following seasons.
The Mechanism of Self-Seeding
Following the pollination of each flower, a small, three-part seed capsule begins to develop in place of the spent bloom. These capsules mature over several weeks, swelling as the tiny seeds inside ripen.
Once the seeds are fully developed and the capsule is dry, the fruit structure exhibits a mechanism known as explosive dehiscence. The capsule’s three walls suddenly contract and burst open, ejecting the seeds with significant force. This biological ejection can scatter seeds several feet away from the parent plant, facilitating the colonization of nearby open soil.
This plant establishes a persistent seed bank in the soil. The seeds are capable of remaining dormant and viable beneath the surface for multiple years, waiting for the right conditions to germinate. This explains why new Johnny Jump Ups can suddenly appear in a spot years after the original plants have vanished. The seeds often require a period of cold stratification, which the winter months naturally provide, before they are ready to sprout in the cooler temperatures of spring.
Managing Unwanted Proliferation
Controlling the spread of Johnny Jump Ups requires interrupting the reproductive cycle before the seed capsules can mature. The most effective strategy for prevention is regular deadheading, which is the removal of spent flowers. By pinching off the fading blooms at the stem, you eliminate the potential for seed capsule formation entirely. This practice has the added benefit of encouraging the plant to produce new flowers, extending the bloom season.
If some seeds have already dropped, a secondary control measure is the application of a thick layer of organic mulch. A two-to-three-inch layer of wood chips or shredded leaves can suppress the light needed for the seeds to germinate successfully. Mulch also physically impedes the progress of any seedlings that do manage to sprout, making them weaker and easier to remove.
For areas where seedlings are abundant, regular, shallow weeding is necessary to remove the young plants before they can flower. Since the seedlings are relatively small and shallow-rooted, they are easily lifted from the soil, especially after a rainfall. It is important to remove these volunteers before they can begin setting their own seed, which can happen quickly in the cool spring and fall weather.
Optimal Environments for Desired Growth
These plants perform best in cool-weather conditions, thriving in locations that receive either full morning sun or partial afternoon shade. While they can tolerate full sun, they will struggle and often go dormant prematurely in the intense heat of a summer afternoon. Placing them where they receive protection during the hottest part of the day will prolong their flowering period.
The ideal soil should be consistently moist, yet possess excellent drainage to prevent root rot. Incorporating organic matter, such as well-aged compost, helps retain moisture while improving soil structure. A slightly acidic to neutral pH is preferred, supporting the robust growth that leads to prolific flowering and seed production.
These characteristics make Viola tricolor an excellent choice for planting in rock gardens, along the edges of borders, or beneath taller, deciduous shrubs. In these locations, the plants will naturally scatter their seeds, and the resulting seedlings will form a low-growing ground cover. Successful self-seeding is most likely to occur when the soil surface is disturbed lightly in the fall, allowing scattered seeds to make good contact with the ground.