Species giant hyssop
 dark purple-blue flower, green leaves, and green stems.

giant hyssop

Agastache 'Black Adder'

Giant hyssop (Agastache 'Black Adder') is an amazing plant species for gardening and plant enthusiasts alike. Its spires of tubular, nectar-rich flowers will draw in all kinds of pollinators, bringing life and color to any garden or outdoor space. Growing up to 8 feet in height, it has striking, dark purple foliage and brightly hued magenta-pink flowers that bloom from mid-summer through early fall. Beyond its beauty, this versatile plant is incredibly low maintenance and deer resistant, thriving in sunny spots and well-drained soils. It's perfect for borders, cut flower and even dried flower arrangements.

Cycle:

Herbaceous Perennial

Watering:

Average

Propagation:

Division,Cutting,Seed Propagation,Layering Propagation

Hardiness Zone:

6 - 9

Flowers:

Smoky red violet Flowers

Sun:

full sun

Leaf:

Yes

Growth Rate:

High

Maintenance:

Moderate

Salt Tolerant:

Yes

Care Level:

Medium

watering

As a drought-tolerant variety, it prefers an occasional watering schedule. During the spring and summer, it should be watered deeply once or twice per week, allowing the soil to dry out between waterings. During the winter, it only needs to be watered once or twice a month. Be sure not to overwater, as this could potentially lead to root rot. In general, it is best to feel the soil before watering to determine if the plant needs additional moisture.

sunlight

Giant hyssop (Agastache 'Black Adder') enjoys plenty of direct sunlight for 6 to 8 hours per day. Planting in full sun is recommended and will help to ensure that this plant species reaches its full size and produces its best blooming performance.

pruning

Pruning is an important part of caring for giant hyssop to help prevent disease and encourage vigorous growth. The best time for pruning is late winter or early spring, before new growth begins. Start by removing dead or damaged stems. Thin out any overcrowded stems to allow more air flow and prevent the plant from becoming too dense. Additionally, it may be beneficial to trim off the tips of the stems. This will encourage the plant to produce thicker and more robust stems. It is important not to prune too much, as it can weaken the stem strength. For most plants, removing no more than 1-third of the stems is recommended. If more aggressive pruning is needed, do so in increments over several years. Giant hyssop is a great option for adding a beautiful, colorful addition to any garden. However, it is important to trim it appropriately to ensure the optimal health and growth of the plant.

Season

Fall
Winter
Spring
Summer
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Starts Flowering

Agastache 'Black Adder' typically starts flowering in late spring or early summer, usually in May or June.

Starts Flowering

Agastache 'Black Adder' typically starts flowering in late spring or early summer, usually in May or June.

Hardiness Map