Anise Hyssop (Agastache foeniculum) is a perennial herb celebrated for its upright spikes of lavender-purple flowers and distinct licorice-scented foliage. This North American native plant provides leaves excellent for culinary uses, such as herbal teas, and strongly attracts pollinators like bees and hummingbirds. Starting this fragrant herb from seed is an economical method for establishing a large patch in the home garden, allowing many plants to be cultivated from a single seed packet.
Preparing Seeds for Successful Germination
Anise hyssop seeds require cold, moist stratification to achieve high germination rates. This process simulates a cold, damp winter, signaling to the seed that spring is the correct time to sprout. For indoor starting, the chilling period should last approximately 30 days.
To stratify, mix the seeds with a moisture-holding medium, such as damp sand or a slightly moist paper towel. Seal the mixture in a plastic bag and place it in a refrigerator, maintaining temperatures between 35 and 40 degrees Fahrenheit. Ensure the medium is moist but not soaking wet to prevent mold.
After 30 days, the seeds are ready for indoor sowing, timed six to eight weeks before the last expected frost date. This timing allows seedlings to develop sufficient strength before transitioning outdoors.
Sowing Techniques and Initial Setup
Once stratified, sow the seeds in a sterile, well-draining seed-starting mix. Lightly pre-moisten the trays or containers before planting. Anise hyssop seeds require exposure to light for successful germination.
Surface-sow the tiny seeds by gently pressing them onto the soil surface without burying them. If needed, use only a very fine dusting of vermiculite or soil to maintain moisture, ensuring the seeds remain exposed to light. Water gently from the bottom up or use a fine mist to avoid dislodging the seeds and maintain consistent moisture.
The optimal germination temperature is 65 to 70 degrees Fahrenheit, often maintained using a heating mat. Immediately place the trays under a direct light source, such as a grow light or a bright windowsill. Providing 14 to 16 hours of light daily encourages robust, compact growth.
Caring for Young Seedlings
Once the seeds germinate and the first true leaves appear, the young plants require careful management. If multiple seedlings sprouted close together, thin them out to prevent overcrowding and improve air circulation. Select the strongest seedling in each container and gently snip the others at the soil line.
As seedlings mature, shift the watering routine from light misting to deeper, less frequent soakings. Allow the top layer of the potting mix to dry slightly between waterings. This promotes stronger, resilient root development and reduces the chance of root rot.
Before permanent transplanting, seedlings must undergo hardening off over seven to ten days. Gradually expose the plants to increasing amounts of outdoor conditions, including sun, wind, and temperature fluctuations. Start with an hour or two in a sheltered, shaded location, and progressively increase the duration and intensity of exposure daily.
Once the danger of frost has passed, transplant the hardened seedlings into their permanent garden location. Anise hyssop performs best in full sun, tolerates partial shade, and requires well-drained soil. Space the seedlings 12 to 18 inches apart, providing ample room for mature growth and ensuring good air flow.