Coreopsis, commonly known as Tickseed, is a cheerful, low-maintenance perennial prized for its long blooming season and bright, daisy-like flowers. This plant, native to North America, produces abundant blossoms from late spring well into the autumn months. To ensure a vigorous display and maximize the flowering period, routine cutbacks must be performed throughout the growing cycle. Understanding the specific timing and technique for pruning is essential for successfully cultivating this popular garden perennial.
Summer Maintenance: Deadheading for Continuous Blooms
The first phase of maintenance begins during the active growing season, typically starting in late spring or early summer as the initial flush of flowers begins to fade. Removing these spent flower heads, a practice known as deadheading, encourages the plant to produce more blossoms. By preventing the plant from setting seed, energy is redirected back into vegetative growth and new flower bud formation.
To deadhead effectively, remove the individual spent flower by cutting the stem just above the nearest set of healthy leaves or a visible side bud. This precise cut stimulates the plant to activate the dormant bud, leading to a new flowering stem. For larger plantings or varieties that produce numerous small flowers, a quicker method called “shearing” can be employed after the main summer bloom has passed, usually mid-season.
Shearing involves cutting the plant back by up to one-third of its height using hedge shears to create a more uniform shape. This mid-summer pruning removes faded blooms and developing seed heads, rejuvenating the foliage and encouraging a robust second or third wave of flowering later in the season. This technique addresses the tendency of Coreopsis to become “leggy” and unkempt after its first heavy bloom cycle.
The Major Fall Cutback: Preparing for Dormancy
The annual, season-ending cutback is performed once the plant has finished blooming and is preparing for winter dormancy. Gardeners have two primary options for this major pruning: late fall after a hard frost, or early spring before new growth emerges. The choice between these two timings depends on local climate, Coreopsis variety, and the gardener’s preference for winter garden appearance.
A fall cutback is performed after the first killing frost has turned the foliage brown, signaling that the plant’s energy has retreated into the crown and roots. This practice is favored for neatness and helps reduce the risk of pests or fungal spores overwintering in dead plant debris. When cutting back in the fall, the plant should be reduced significantly, leaving only a short basal rosette or stems cut back to approximately four to six inches above the ground.
Leaving the dead foliage standing until early spring is often recommended, especially in colder climates. The dead stems and leaves provide insulation, protecting the plant’s crown from winter temperature fluctuations. The standing seed heads also offer a natural food source for birds, such as goldfinches, throughout the winter months. The spring cutback is completed just as the first signs of new, green growth appear at the base of the plant.
Essential Tools and Technique
Regardless of the season, using the correct tools and proper technique ensures clean cuts that heal quickly and minimize stress on the plant. Sharp, clean hand pruners are the preferred tool for precise deadheading and the final major cutback. Using dull tools can crush or tear the stems, creating ragged wounds that are more susceptible to disease entry or pest infestation.
Before and after use, especially when moving between different plants, it is important to clean cutting tools to prevent the spread of plant pathogens. Begin by removing all visible soil, sap, and debris from the blades, as this organic matter can interfere with the disinfection process. A stiff brush and soap and water can accomplish this initial cleaning.
Following cleaning, the tools should be sterilized using a disinfectant like a solution of 70% isopropyl alcohol or a 10% bleach solution. Isopropyl alcohol is effective and can be quickly wiped or sprayed onto the blades, which is beneficial for quick sanitation between cuts. Keeping the tools clean supports the long-term health of the entire garden.