Butterflies enjoying the Flowers of Agastache  Black Adder Agastache black adder flowers Agastache Black Adder in the garden Agastache Black Adder in the wild garden

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Agastache Black Adder

Agastache foeniculum 'Black Adder'

Agastache Black Adder is a reliably hardy perennial that has licorice scented foliage and is a bee, butterfly and hummingbird magnet!

Growzone: 6-9

As Low As: $19.95

1. Choose Size & Quantity
Size Price Quantity
1 Gallon Pot $19.95
2. Choose Recommended Add-Ons
Product Price Quantity
Espoma Bio-Tone Starter Plus $16.95
Espoma Flower-Tone 4lb bag $16.95

California Residents: This product can not be shipped to California at this time. Browse products that can be shipped to California here.

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Agastache Black Adder Plants for Sale Online


Agastache Black Adder produces numerous bottle-brush flowers of vivid Violet-blue from mid-summer to frost on a compact, rounded plant. It has been hardy for us in the ground reliably winter after winter.

About Your Agastache Black Adder

Black Adder hyssop is a long-blooming selection for the middle to back of the border, featuring long wands of vivid blue-violet flowers bracts. Foliage is dark green and licorice-scented. Attractive to butterflies and hummingbirds. Flowers are excellent for cutting. Pinch in June to keep plants compact if desired.


Growing Zone: 6-9
Mature Height: 2 to 3 feet
Mature Width: 2 to 3 feet
Classification: 2 to 3 feet
Sunlight: Full Sun
Habit: Upright, clump forming
Flower Color: Bright vivid blue
Flowering Season: Mid-June through frost
Foliage: Green
Soil Condition: Prefers dry, average to sandy soil, wont tolerate wet soil in winter
Water Requirements: Water well until established
Uses: Extremely attractive when used as a focal point in the mixed border, mass planting. Attracts pollinators and hummingbirds.
This Plants Growzone: 6-9
Agastache Black Adder Hardiness Zone

How to Care for Agastache Black Adder

We suggest when planting your newly purchased Agastache Black Adder plants that you dig a hole twice as wide as the root system but not deeper. Depending on the quality of your existing soil you may need to add a locally sourced compost or topsoil to the back-fill soil. We do not recommend using straight topsoil or compost as a back-fill soil because more times than not these products will retain entirely to much moisture and will cause the root system to rot. Adding compost or topsoil will help the young feeder roots to spread through the loose, nutrient rich soil, much easier than if you used solely the existing soil which more times than not will be hard and compacted. The most common cause of plant death after transplanting is planting the new plant to deep. That is why we do not recommend planting in a hole any deeper than the soil line of the plant in the pot. A good rule is that you should still be able to see the soil the plant was grown in after back-filling the hole. Agastache Black Adder does prefer drier soils in the winter so if there was ever a plant that we would recommend not adding topsoil or compost this is one. Bio-tone starter fertilizer is a great starter fertilizer that provides plants with mycorrhizae fungus. It is a naturally occurring beneficial fungus that colonizes on the new growing roots of plants. It creates a barrier between the roots of the plant and fungus and pathogens that can cause root rot. We love this product and use it on all plants we install in our own gardens. Bio-tone is a gardener’s best friend and can help guarantee your success.


Frequently Asked questions

How do I water Agastache Black Adder?

How do I fertilize Agastache Black Adder?

How do I mulch Agastache Black Adder?

How do I prune Agastache Black Adder?


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