The key to growing the Agastache (Hummingbird Mints) is to find a hot, sunny planting site with quick draining soil of low fertility. Clay and rich, water-retentive loamy soils are a poor match for these plants. Agastache needs 'lean,' well-drained soils, and they prefer gravel mulches and appreciate deep but infrequent watering after their second growing season.
Learn More: How To Create Well-Drained Soil
Fall Care & Maintenance
It is essential that you not cut back hummingbird mints in the fall.To improve winter-hardiness, and encourage re-seeding, leave the stems intact over the winter. Nutrients from the stems help to feed the crown and fortify it against winter cold.
Don’t over-feed; a fall top dressing of compost and Yum Yum Mix is all they need to flourish. Too much high nitrogen fertilizers will shorten their lifespan and make the plants floppy.
Wait until mid-spring in your area (a month or so before last frost) to cut them back. In mid-spring, remove old stems just above the new foliage, about 4 or 5 inches above ground level.
Growing Agastache In Non-Western Regions
In zones 5 and 6, or areas of the country with cold, wet winters, plant on sunny south or west-facing slopes or in raised beds. The soil needs to be sandy, infertile and fast-draining. The plant's crown should be planted high and then mulched with crushed gravel to keep it drier during cold, wet weather. 'Blue Fortune' and Korean hyssop are best varieties for higher rainfall areas east of Mississippi.
Learn More: All About Agastache: Hummingbird Favorites For The Watwerwise Garden