Pansies, scientifically known as Viola tricolor var. hortensis, are popular cool-weather flowering plants often grown as annuals or biennials. When their vibrant display begins to fade and the stems stretch out, many gardeners wonder if they can revive the color. Pansies can rebloom if they are properly cut back, effectively restarting their flowering cycle. This need for pruning is a direct result of the plant’s natural biological imperative.
Understanding the Need for Pruning
Pansies stop producing flowers and begin to develop a leggy, sprawling habit as a result of their reproductive strategy. The primary motivation for any flowering plant is to produce seeds to ensure the next generation. Once a flower is pollinated and fades, the plant diverts its energy from creating new blossoms to developing the seed within the spent flower head. This shift means fewer resources are available for new flower bud formation, leading to a decline in the number and size of blooms. Pruning intervenes in this cycle by removing the seed-setting material, which effectively tricks the plant into focusing its energy back into generating new flowers and a more compact shape.
The Step-by-Step Process for Cutting Back
The process of cutting back pansies involves two distinct methods: routine maintenance and corrective shearing.
Routine Maintenance (Deadheading)
Routine maintenance, or deadheading, involves removing individual spent flowers along with their entire stem (pedicel) back to where it meets the main plant or a healthy leaf node. This preventative measure should be done continuously to keep the plant in flower-producing mode and halt seed development.
Corrective Shearing
When the plant has become significantly leggy with long, stretched stems and few flowers, a more aggressive corrective cutback is necessary. This involves shearing the plant, which should be done with clean, sharp shears or scissors. Reduce the overall stem length by about one-third to one-half, or down to a few inches of growth above the crown. Always make the cut just above a leaf node, the point on the stem where a leaf or new shoot emerges. Cutting here encourages the plant to branch out, leading to a fuller, bushier appearance and a fresh flush of blooms.
Supporting the Rebloom: Environmental Factors
Pruning is the mechanical trigger for rebloom, but the plant requires external support to fuel this renewed effort.
Fertilization
Immediately following a major cutback, applying a balanced, water-soluble fertilizer is necessary to supply the energy for new growth. Pansies thrive with a balanced NPK ratio, such as 10-10-10 or 20-20-20. Use a bloom-boosting formula that avoids excessive nitrogen, as too much nitrogen encourages leafy growth over flowers. Always water the pansies thoroughly before applying fertilizer to prevent root burn and ensure nutrient uptake.
Moisture and Temperature
Consistent moisture is important for the rebloom process, requiring about one inch of water per week, adjusted for rainfall and temperature. The soil should be kept consistently moist but never waterlogged. Pansies are cool-weather plants that perform best when temperatures are between 40°F at night and 60°F during the day. Rebloom is most successful during the mild conditions of early spring and fall. Cutting back pansies during the peak of summer heat, especially when temperatures consistently exceed 70°F, may not result in a robust rebloom, as the heat stresses the plant.