Images Depict Mature Plants
Agastache Black Adder
Agastache x. 'Black Adder'
Black Adder Agastache is a great pick when you want a pollinator plant with a little more drama. The dark buds and purple flower spikes give it strong presence in a sunny border, while the fragrant foliage, deer resistance, and drought tolerance make it practical for real garden conditions. I especially like it planted near walkways, patios, and pollinator beds where you can enjoy the scent of the foliage and watch hummingbirds, bees, and butterflies work the flowers.
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Dark Purple Spikes for Pollinator-Packed Gardens
Dramatic flower spikes from dark buds.
Black Adder Agastache produces upright spikes of smoky violet-purple flowers that emerge from nearly black buds, giving the plant a deeper, more dramatic look than many lighter blue Agastache varieties. The tall bottlebrush-style blooms bring strong vertical color to sunny borders from summer into early fall.
A pollinator magnet with real garden movement.
This perennial is a standout for bringing bees, butterflies, hummingbirds, and beneficial insects into the landscape. The nectar-rich flower spikes keep pollinators active through the warm months, making Black Adder Agastache a smart choice for pollinator gardens, hummingbird plantings, and wildlife-friendly borders.
Fragrant foliage deer tend to avoid.
The aromatic green foliage has a minty, anise-like scent when crushed, adding another layer of interest beyond the flowers. That strong fragrance also helps make Black Adder Agastache less appealing to deer and rabbits, especially compared to softer, less aromatic perennials.
Built for full sun and well-drained soil.
Black Adder Agastache thrives in full sun and performs best in well-drained soil that does not stay wet, especially during winter. Once established, it handles heat and dry spells well, making it a strong fit for low-water gardens, sunny slopes, dry borders, and leaner garden soils.
Easy to pair in colorful perennial designs.
The rich purple flower spikes pair beautifully with coneflowers, black-eyed Susans, yarrow, catmint, salvia, ornamental grasses, and Russian sage. Use it in groups for a bold pollinator display, or repeat it through a sunny border to add rhythm, height, and late-season color.
| Hardiness Zone: | 6-9 |
|---|---|
| Mature Height: | 2 to 3 Feet |
| Mature Width: | 1.5 to 2 Feet |
| Sunlight: | Full sun; tolerates light shade but blooms best in full sun |
| Soil | Well-drained soil; performs best in average to lean soil and dislikes wet winter soil |
| Water | Water regularly after planting; drought tolerant once established |
| Bloom Time / Color | Summer into early fall; smoky violet-purple to blue-purple flower spikes from dark buds |
| Foliage: | Fragrant green foliage with minty, anise-like scent |
| Ornamental Features | Dark buds, purple bottlebrush flower spikes, aromatic foliage, upright habit, long bloom season |
| Wildlife Value | Attracts hummingbirds, butterflies, bees, and other beneficial pollinators |
| Resistance | Deer resistant, rabbit resistant, drought tolerant once established, heat tolerant, and generally low maintenance |
| Landscape Uses | Pollinator gardens, hummingbird gardens, cottage gardens, sunny borders, herb gardens, mass plantings, meadow-style gardens, dry gardens, containers, and low-water landscapes |
How to Care for Agastache Black Adder
Be sure to read our planting instructions to ensure a healthy and happy Black Adder Agastache Plant for years to come!
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How should I plant Black Adder Agastache?
Plant Black Adder Agastache in a full sun location with well-drained soil. Choose a spot that receives at least 6 hours of direct sun per day, and avoid heavy, wet soil where roots may stay soggy, especially through winter. Dig a hole about twice as wide as the root ball and set the crown level with the surrounding soil. Backfill with native soil, water deeply, and space plants about 18 to 24 inches apart to allow room for mature growth and good airflow.
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How often should I water Black Adder Agastache after planting?
Water Black Adder Agastache regularly during the first growing season while the roots establish. Keep the soil lightly moist after planting, but avoid overwatering because Agastache performs best when drainage is sharp. Once established, Black Adder Agastache becomes drought tolerant and usually needs less supplemental water than many flowering perennials. During extended heat or dry periods, water deeply but infrequently to encourage strong roots and steady bloom performance.
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When should I fertilize Black Adder Agastache?
Fertilize Black Adder Agastache lightly in spring only if your soil is very poor. In most garden settings, a small amount of compost or a light application of balanced, slow-release fertilizer is enough. Avoid heavy feeding or overly rich soil, which can encourage soft, floppy growth instead of sturdy flower spikes. This perennial often performs best in average to lean soil with good drainage and plenty of sun.
When and how should I prune Black Adder Agastache?
Prune Black Adder Agastache in late winter or early spring by cutting old stems back close to the ground before new growth begins. Leaving some stems standing through winter can add texture and provide shelter for beneficial insects. During the growing season, deadhead spent flower spikes to keep the plant tidy and encourage continued blooming. Avoid cutting the plant back hard too late in the season in colder climates, since tender new growth may not harden off before winter.
