Agastache, often known as Hummingbird Mint, is a favored plant for its aromatic foliage and vibrant, spiky blooms. These qualities make it particularly attractive to pollinators, including hummingbirds and various beneficial insects. Propagating Agastache offers a rewarding way to expand your garden, fill new spaces, or share these beautiful plants with others.
Propagating Agastache from Seed
Growing Agastache from seed is a practical method requiring specific conditions. You can sow seeds indoors approximately 6 to 8 weeks before the last anticipated frost date in your region, or directly sow them outdoors in the spring after the danger of frost has passed. Fall sowing is also an option, allowing seeds to naturally stratify over winter and emerge in spring.
Agastache seeds need light to germinate, so they should be surface-sown or covered with only a very thin layer of fine soil. A well-draining seed-starting mix provides an ideal environment. Maintain consistent moisture in the seed-starting medium, avoiding waterlogging, and aim for an ideal germination temperature between 68-75°F (20-24°C). Germination typically occurs within 14 to 21 days.
Once seedlings develop their first set of true leaves and are large enough to handle, they can be transplanted into individual pots. Before moving young plants permanently outdoors, gradually acclimate them to external conditions over a period of one to four weeks. This hardening-off process involves exposing them to increasing periods of outdoor light, temperature fluctuations, and wind, preparing them for their final garden location.
Propagating Agastache from Cuttings
Propagating Agastache from stem cuttings is an effective way to create new plants that are genetically identical to the parent. The best time to take cuttings is during late spring to early summer when the plant is actively growing and producing tender new shoots. Select healthy, non-flowering stems, as these tend to root more readily.
A suitable cutting should be about 4-6 inches long, with a clean cut made just below a leaf node. Remove the leaves from the bottom inch or two of the stem to prevent rot and expose rooting points. While not always necessary, dipping the cut end in a rooting hormone powder can encourage faster and more successful root development.
Plant the prepared cuttings into a well-draining rooting medium, such as a mix of perlite and sand, or a general-purpose compost with added grit. Insert the cutting into the medium, ensuring the bottom node is buried, and gently firm the soil around it. To create a humid environment conducive to rooting, cover the pot with a clear plastic bag or a humidity dome. Place the covered pot in a location with bright, indirect light and maintain consistent moisture in the rooting medium. Roots typically form within 2-4 weeks.
Propagating Agastache by Division
Division is a straightforward method for propagating mature Agastache clumps, offering a way to rejuvenate older plants while increasing your stock. This process is typically best performed in early spring, just as new growth begins to emerge, or in the fall. Dividing an established plant every three to five years can help maintain its vigor and prevent overcrowding.
To divide an Agastache, carefully dig up the entire parent plant, preserving the root ball. Once lifted, gently separate the root ball into smaller sections. Each new section should have a healthy portion of roots and at least one or more shoots.
A sharp spade or garden knife can be used to cleanly cut through the root ball if it is too dense to pull apart by hand. Replant the newly divided sections immediately into prepared garden spots at the same depth as the original plant. After replanting, water thoroughly to help settle the soil around the roots and reduce transplant shock, ensuring the new plants establish well.
Caring for Your New Agastache Plants
Newly propagated Agastache plants require specific care for successful establishment and healthy growth. Consistent moisture is important for young plants, especially during their first growing season, to help them develop a robust root system. However, avoid overwatering, as Agastache prefers well-draining soil and can be susceptible to root rot in soggy conditions.
Agastache thrives in full sun, ideally receiving at least six to eight hours of direct sunlight daily, which promotes optimal flowering and growth. While established plants are drought-tolerant, young ones benefit from regular watering until their root systems are well-developed. The soil should remain well-draining; incorporating sand or grit can improve drainage if needed.
Fertilization for young Agastache plants should be minimal, as these plants generally perform well in lean soils. An application of compost or a light, balanced, slow-release fertilizer in the spring can support healthy development without encouraging excessive foliage growth at the expense of blooms. Regularly monitor new plants for any signs of common garden pests like spider mites or aphids, and address issues promptly to maintain plant health.