perennialN. America Native

Giant Hyssop 'Black Adder'

Name: Giant Hyssop 'Black Adder'
Brand: Agastache
Availability: InStock

Agastache foeniculum 'Black Adder'

$14.95

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Essentials

At a Glance

Plant Type

Perennial

Height

42 inches

Width

18 inches

Light

Full Sun, Partial Sun

Zones

6, 7, 8, 9

Water

Moderate

Humidity

Average

Lifespan

Perennial

Native To

North America

Toxicity

Non-toxic

The Story

Plant Bio

A hardy perennial with aromatic foliage and tall spikes of flowers. Black Adder is known for its dark colored flowers and ability to attract pollinators.

Bloom Period:

EarlyLate

Uses & Benefits:

Provides aromatic foliage and striking purple flowers that attract pollinators.

Herb used in culinary dishes and herbal teas for its flavor and medicinal properties.

Supports bees and butterflies, promoting pollinator health.

Marketplace

Where to Buy

Rare Roots

<1 Gal Pot

In Stock$14.95

Spring Hill Nursery

Bareroot

In Stock$22.99

Sooner Plant Farm

1+ Gal Pot

In Stock$25.00

Shipping costs Year-round shipping Free shipping

Planting

How to Grow

Tuck seeds into well-draining soil in early spring for best germination.
Mist cuttings regularly to maintain humidity and encourage root development.
Transplant seedlings once they are sturdy and after the last frost date.
Water deeply but infrequently, allowing soil to dry between watering.
Fertilize monthly with a balanced, organic fertilizer during the growing season.
Prune back spent flower stalks to promote bushier growth and more blooms.

Pro Tip

Use well-draining, slightly sandy soil and full sun for vigorous growth.

Keep It Thriving

Care Guide

Do

Water deeply during dry spells 🌱
Prune after flowering to encourage new growth
Mulch to retain soil moisture and suppress weeds

Don't

Avoid overwatering to prevent root rot ❌
Don’t overcrowd plants to ensure good air circulation
Never fertilize late in the season to prevent legginess

Seasonal Care Calendar

Task	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Deadhead
Prune
Winter Prep

Watch Out For

Pests & Diseases

Common Pests

Common Diseases

In the Garden

Landscape Uses & Companions

Landscape Uses

Fragrant herb borderSilver-leafed perennial bedWildflower meadow accent

Companion Plants

Echinacea Lavender Salvia Yarrow Coreopsis

Multiply

Propagation Methods

Good to Know

Common Questions

Giant Hyssop 'Black Adder' questions

What zones can Giant Hyssop 'Black Adder' grow in?

Giant Hyssop 'Black Adder' is hardy in USDA Zones 6–9. Inside that range it survives winter in the ground; outside it, grow it as an annual or a container plant you protect.

Is Giant Hyssop 'Black Adder' deer resistant?

Yes — Giant Hyssop 'Black Adder' is rated deer-resistant. Deer typically pass it over, though extreme hunger can override any plant's defenses.

When does Giant Hyssop 'Black Adder' bloom?

Giant Hyssop 'Black Adder' typically blooms in mid-summer through late summer. Exact timing shifts a week or two with your zone — Sow's bloom calendar maps it to your garden.

Does Giant Hyssop 'Black Adder' need full sun?

Giant Hyssop 'Black Adder' does best in full sun to part shade. In hot climates, afternoon shade keeps blooms fresher longer.

Is Giant Hyssop 'Black Adder' drought tolerant?

Yes — once established (usually after the first full season), Giant Hyssop 'Black Adder' handles dry spells with minimal watering. Water deeply its first year to build the root system that makes that possible.