Nepeta, commonly known as Catmint, is a popular herbaceous perennial recognized for its durability and long-lasting, aromatic blooms. To maintain its signature mounded shape and ensure continuous flowering, this plant requires consistent maintenance pruning. Without regular cutting back, the stems can quickly become sparse and elongated, leading to a sprawling or “leggy” appearance and a reduction in flower production. Pruning promotes dense, vigorous growth from the plant’s base, supporting a healthier, fuller display.
Early Season Shaping
The first major cut of the year sets the foundation for the plant’s structure and overall size. This initial shaping should be performed in late winter or early spring, typically just as new basal growth begins to emerge from the crown. The goal is to remove all the old, gray, and woody stems from the previous growing season.
Cutting back the old growth allows sunlight and air to reach the developing shoots at the plant’s base. This encourages the plant to produce multiple new stems, resulting in a much fuller, more compact structure. This cleanup usually occurs before the last hard frost has passed, ensuring the plant can focus its energy on new seasonal growth.
Mid-Summer Maintenance for Rebloom
Pruning occurs immediately following the first large flush of spring flowers. This mid-season maintenance, often referred to as a hard shear, is performed to stimulate a second wave of blooms. Without this cut, the plant would shift its resources into setting seed, which halts further flowering and causes the stems to flop outward.
The ideal time for this cut is typically from late June to early July, or whenever the majority of the spring flowers have faded. To effectively trigger a rebloom, you must cut the entire plant back significantly, removing approximately one-third to one-half of its height. This aggressive shearing forces the plant to divert energy into new vegetative growth, resulting in fresh foliage and a subsequent, usually smaller, bloom period that lasts until fall.
Essential Cutting Techniques
The physical process of cutting back Nepeta should prioritize clean, precise cuts to minimize stress and prevent disease. Using sharp, sanitized tools, such as bypass pruners or hedge shears, is necessary to avoid crushing the stems, which can leave ragged edges susceptible to fungal infection. When making any significant cut, aim to shear the stem just above a leaf node or a visible new growth bud.
Cutting back to a node encourages the plant’s energy to be directed to that specific point, promoting healthy lateral or basal growth. For a major cutback, such as the mid-summer shear, the entire plant is reduced to a uniform height, generally leaving a cushion of growth between four to six inches tall. This remaining foliage is necessary for photosynthesis, allowing the plant to quickly gather the energy needed for its regeneration.
Preparing Nepeta for Winter
The final preparation for the dormant season involves a choice between two distinct approaches. One strategy is to perform a hard cutback in late fall, after the foliage has naturally yellowed and died back following the first heavy frost. This method involves reducing the stems to within two to three inches of the ground, which tidies the garden and simplifies the following spring’s cleanup.
The alternative approach is to leave the spent stems standing through the winter months, delaying the cut until late winter or very early spring. Leaving the stems provides a slight degree of insulation for the crown and offers habitat or shelter for overwintering beneficial insects. If this approach is chosen, the entire mass of dead material must be completely removed before new green shoots begin to emerge in the spring for a clean, healthy start to the new growing season.