Agastache, commonly known as Anise Hyssop or Hummingbird Mint, is a genus of aromatic herbaceous perennials valued for their long-lasting flower spikes and fragrant foliage. This plant belongs to the Lamiaceae family and is native to regions of North America, Mexico, and Asia. The appealing tubular flowers, which appear in shades of blue, purple, pink, and orange, attract various pollinators, including bees, butterflies, and hummingbirds. Gardeners frequently seek ways to multiply their stock, and the following methods describe strategies for reproducing this plant suited to different varieties and purposes.
Growing Agastache from Seed
Starting Agastache plants from seed is a highly effective method, though it is primarily suited for species rather than hybrid varieties, as hybrids may not breed true to the parent plant. Many Agastache seeds require a period of cold, moist conditioning, known as stratification, to break dormancy. This process can be simulated by refrigerating seeds layered between damp paper towels for four to six weeks before sowing indoors.
For indoor sowing, begin approximately six to eight weeks prior to the final expected frost date in spring. Use a sterile, well-draining seed-starting mix and barely cover the tiny seeds, as they need light exposure to germinate successfully. Maintain a consistent soil temperature near 70 to 75 degrees Fahrenheit. Germination typically occurs within two to three weeks.
An alternative approach is direct sowing in late autumn or early winter, allowing the natural cold and moisture cycle to provide the necessary stratification. When sowing directly, gently press the seeds into the soil surface after the first hard frost. These seeds will remain dormant through the winter and sprout when soil temperatures rise in the spring.
Propagating Through Stem Cuttings
Propagation using stem cuttings is the preferred method for duplicating specific hybrid varieties, guaranteeing the new plant is a genetic clone of its parent. The ideal material is softwood or semi-hardwood, referring to the pliable, non-woody growth taken during late spring or early summer. Select a healthy, non-flowering stem section about four to six inches in length from the current season’s growth.
Make a clean, angled cut just below a leaf node, as this is the point where rooting hormones are naturally concentrated. Remove the leaves from the bottom one-third of the cutting to prevent rotting once inserted into the medium. Dipping the cut end into a powdered or liquid rooting hormone increases the speed and percentage of successful root formation.
The cuttings should be placed into a prepared medium consisting of materials like perlite and peat moss or coarse sand, which provides superior aeration and drainage. Creating a high-humidity environment, such as covering the pot with a clear plastic bag or a humidity dome, is important to minimize water loss. Place the setup in a warm area with bright, indirect light; roots should begin to form within four to six weeks.
Dividing Established Clumps
Division is the quickest way to produce larger, established specimens, and this method is best suited for clumping varieties of Agastache. Division should be performed either in early spring, just as new growth begins to emerge, or in early fall, allowing sufficient time for the divisions to establish roots before winter dormancy. Carefully lift the entire plant from the soil using a garden fork.
Once the clump is out of the ground, shake off excess soil to expose the root crown. Use a sharp, clean garden knife or spade to slice the rootball into smaller sections. Each resulting division must contain a healthy portion of the root system and at least one viable shoot or bud.
Replant the separated sections immediately at the same depth they were previously growing, firming the soil gently around the roots. Division multiplies the stock and rejuvenates older plants that may have begun to decline in vigor or have a dead center. Divisions should be watered thoroughly immediately after replanting to settle the soil and reduce transplant shock.
Care Requirements for Young Plants
Specific care is necessary to ensure the successful establishment of new Agastache plants. The initial focus must be on consistent moisture levels; the growing medium should be kept evenly moist but never saturated, as young roots are susceptible to rot.
Newly rooted cuttings and seedlings require bright light but should be protected from intense, direct sunlight, which can scorch foliage. Once seedlings have developed at least two sets of true leaves, or cuttings show vigorous new growth, they need a gradual introduction to outdoor conditions. This process, called hardening off, involves progressively exposing the plants to increasing durations of direct sun and wind over seven to ten days.
When the risk of frost has passed, plants can be transplanted into their final garden locations. Agastache thrives in full sun and requires soil that drains well. Planting the young specimens in a location with lean soil encourages robust root development and prevents the lanky, floppy growth associated with overly rich soil compositions.