Overwintering guide
How to overwinter agastache 'black adder'
Winter watering
No winter watering needed in open ground. Containers only need water in long dry, frost-free spells.
The mistake that kills agastache 'black adder' in winter
Cutting agastache 'black adder' hard back in autumn "to tidy up". That removes the growth that shelters the crown, and on some plants removes next season's flower buds entirely.
More agastache 'black adder' care
Overwintering agastache 'black adder' — FAQ
Does agastache 'black adder' need to come indoors for winter?
Agastache 'Black Adder' is hardy to roughly USDA zone 5 — winter lows around -29°C. That means it can stay outside all winter in most temperate gardens. Agastache 'Black Adder' is properly hardy and overwinters outside without fuss. Tidy away anything dead or diseased, apply a mulch over the crown to steady soil temperatures, and otherwise leave it alone — many hardy plants actually need a cold period to flower and grow well the following year. Save hard pruning for the right season rather than doing it in autumn.
When should I move agastache 'black adder' for winter?
Tidy and mulch in late autumn; leave the plant undisturbed until spring.
How often should I water agastache 'black adder' in winter?
No winter watering needed in open ground. Containers only need water in long dry, frost-free spells.
What kills agastache 'black adder' over winter?
Cutting agastache 'black adder' hard back in autumn "to tidy up". That removes the growth that shelters the crown, and on some plants removes next season's flower buds entirely.