The key to growing the Agastache (Hummingbird Mints) is to find a hot, sunny planting site with quick-draining soil of low fertility. Agastache needs 'lean,' well-drained soils. Clay and rich, water-retentive loamy soils are a poor match for these plants. Agastache will act like annuals when grown in rich, fertile soils with too much water and fertilizer. They’ll grow and flower lushly, but are most likely to perish over the winter.
Mulching is only necessary in arid climates. Use crushed gravel at a depth of 1 to 2 inches.
Agastache 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 the best varieties for higher rainfall areas east of Mississippi. Learn more about choosing the right Agastache varieties for your garden in our article: All About Agastache.