Catmint (Nepeta) is a robust perennial herb recognized for its aromatic, gray-green foliage and long-lasting spikes of lavender-blue flowers. Belonging to the mint family (Lamiaceae), it is extremely hardy and thrives across USDA Zones 3 through 9. Gardeners transplant Nepeta to control its expansive, mounding habit or to relocate it to a more appropriate spot in the landscape. A successful move depends on carefully executing the process to minimize root disturbance and limit stress on the plant.
Selecting the Timing and Preparing the Site
The most successful transplantation occurs when the plant is not actively blooming or dealing with extreme weather conditions. The ideal time is either in early spring, just as new growth begins, or in the early fall after the summer heat has passed. Moving the plant during these cooler periods allows the roots to establish themselves before the stress of summer or winter. To minimize transplant shock, complete the move on an overcast day or late in the afternoon when the sun is less intense.
Preparation of the new planting site should be completed before the plant is dug up to ensure a swift transition. Catmint prefers well-drained soil, which prevents root rot, and it is not demanding regarding fertility. Dig a receiving hole approximately twice the width of the current root ball but no deeper. The wider hole gives the fibrous roots ample space to spread into loosened soil, encouraging new growth.
Before excavation, thoroughly water the established catmint about 24 hours in advance of the move. This deep pre-watering hydrates the plant’s tissues and helps the soil cling tightly to the root mass. Keeping the root ball intact during lifting is crucial. A moist, cohesive root ball is less likely to crumble, protecting the fine feeder roots essential for nutrient and water absorption in the new location.
Excavating and Replanting Catmint
When ready to move the catmint, use a sharp spade to cut a wide circle around the perimeter of the plant’s base. The goal is to create a root ball large enough to support the top growth, typically 8 to 12 inches in diameter for a mature clump. Drive the spade straight down into the soil to cleanly sever the roots, working around the entire circumference.
Once the circle is cut, gently rock the spade under the root mass to lift the entire clump. Catmint often grows in an expanding clump, offering a good opportunity to divide the plant by slicing straight through the center with the spade if the clump is large. Handle the excavated root ball with care, using burlap or a tarp to carry it to the prepared hole without causing it to break apart.
Carefully set the root ball into the new hole, ensuring the plant’s crown (where the stems meet the roots) is level with or slightly above the surrounding grade. Planting too deep can lead to stem rot and is a common cause of transplant failure. Begin backfilling the hole with the excavated soil, mixing in compost if the original soil quality is poor. As you fill, lightly tamp the soil with your hands to collapse any air pockets that could dry out the delicate new roots.
Essential Post-Transplant Care
Immediate care following the move is paramount to the catmint’s successful establishment, prioritizing root development over foliage growth. After backfilling, give the newly planted catmint a deep, thorough watering to settle the soil and eliminate remaining air pockets. This initial watering is crucial for signaling the plant to begin its recovery process.
To further reduce stress on the root system, prune the catmint immediately after transplanting. Use clean shears to cut back about one-third of the total foliage mass. This reduces the amount of water the leaves demand through transpiration. This action allows the plant to focus its limited energy reserves on generating new roots instead of sustaining existing top growth.
For the first two to four weeks following the move, catmint requires consistent, deep watering to encourage a robust new root system. Unlike established catmint, which is drought-tolerant, the transplanted perennial needs the soil to remain evenly moist to support healing. Monitor the plant for signs of transplant shock, such as sudden wilting or yellowing leaves, which indicates insufficient moisture or too much intense sun. Avoid applying fertilizer during this initial establishment period, as the high salt content can damage newly forming root tips.