Catmint ($Nepeta$ species) is a perennial recognized for its silvery-green foliage, long-lasting lavender-blue flowers, and general hardiness. As a member of the mint family ($Lamiaceae$), this resilient, drought-tolerant plant forms attractive, mounding clumps, making it an excellent choice for borders and mass plantings. Multiplying catmint is straightforward, with several reliable methods available to increase your stock and rejuvenate older specimens.
Propagating by Division
Division is the most dependable and fastest method for propagating catmint, yielding established plants ready to grow immediately. The optimal time is in early spring as new growth emerges, or in early fall after the summer heat has passed, allowing root sections to establish themselves before winter.
Lift the entire established clump from the soil using a garden fork or spade, digging wide enough to preserve the root mass. Once the root ball is out, use a sharp, sterilized knife or spade edge to cut it into smaller sections. Ensure each new piece retains a portion of the root system and several viable growth buds or shoots from the crown. Replant divisions immediately into a prepared bed at the original depth, then water thoroughly to settle the soil.
Propagating by Stem Cuttings
Taking stem cuttings allows for the rapid multiplication of a specific cultivar, bypassing the genetic variability of seed propagation. Soft-tip cuttings, taken from tender, non-woody new growth, are the most successful and should be harvested in late spring or early summer. Select healthy, non-flowering stems and cut 3- to 4-inch sections just below a leaf node, where root-forming cells are concentrated.
Strip the leaves from the lower two-thirds of the stem to prevent rotting once inserted into the medium. While catmint often roots easily without assistance, dipping the cut end into a powdered rooting hormone can accelerate root formation. Insert the prepared stems into a sterile, well-draining medium, such as a mix of perlite and peat moss, ensuring the exposed nodes are buried. Place the container in a bright area out of direct sunlight and maintain consistent moisture for the next few weeks.
Starting Catmint from Seed
Starting catmint from seed is the slowest method of propagation, but it is an economical way to produce a large number of plants, especially for non-hybrid varieties. Many perennial seeds benefit from cold stratification, which mimics the natural winter cycle to break dormancy. Achieve this by placing seeds in a moist medium, like damp sand or vermiculite, sealing them in a plastic bag, and refrigerating for 4 to 6 weeks.
Sow the seeds indoors 6 to 8 weeks before the last expected frost by pressing them lightly into the surface of a seed-starting mix. Catmint seeds require light for germination, so cover them only with a very thin layer of soil or vermiculite. Maintain a consistently moist environment and a temperature around 65 to 70°F; germination can occur within 10 to 40 days. Once seedlings have developed a few sets of true leaves, they are ready to be transplanted into individual pots.
Caring for Newly Propagated Plants
The first few weeks after propagation are important for the establishment of new catmint plants, whether they are divisions, rooted cuttings, or seedlings. Divisions and new transplants should be kept consistently watered, receiving about an inch of water per week, until vigorous new growth is observed.
Place newly potted cuttings and seedlings in a location that receives bright, indirect light until a robust root system has formed. Once the roots begin to fill the pot, or when all danger of frost has passed, the new plants can be moved to their permanent location. Catmint performs best in full sun, which encourages a dense, compact growth habit, and once established, its drought tolerance means it requires little supplemental watering.