Plant Type

Perennial, Herb

 

Height Range

1-3'

 

Flower Color

Red, Violet

 

Flower Season

Summer, Fall

 

Leaf Color

Green

 

Bark Color

n/a

 

Fruit Color

n/a

 

Fruit Season

n/a

Sun

Full, Half

 

Water

Low, Medium

 

Growth Rate

Fast

 

Soil Type

Sandy, Clay, Loam

 

Soil Condition

Average, Rich, Poor, Well-drained, Dry

 

Soil pH

Neutral, Basic

 

Adverse Factors

n/a

Design Styles

English Cottage, Mediterranean, Ranch, Spanish

 

Accenting Features

Fragrance, Showy Flowers

 

Seasonal Interest

Summer

 

Location Uses

Perennial Border, Raised Planter

 

Special Uses

Container, Small Spaces

 

Attracts Wildlife

Hummingbirds, Butterflies

'Black Adder' is an upright, clump-forming giant hyssop that grows to 2 to 3 feet tall and about 2 feet wide. It has a long summer-to-frost season of bloom, with tubular, smoky red-violet flowers that emerge from nearly black buds that bloom in showy, bottle-brush, spikes. Aromatic (anise/licorice scented), lance-shaped to ovate leaves are blue green. Flowers are attractive to bees, hummingbirds and butterflies. Not as drought tolerant as its desert kin, but still a worthwhile addition to the herb garden.

Grow in average, dry to medium moisture, well-drained soils in full sun to part shade, though best in full sun. Good soil drainage is essential. Plants will perform poorly and may not survive winter in unamended clay soils or over-watered soils. Plants tolerate heat and some dry soils once established. Deadhead spent flower blooms to promote additional bloom. Cut back the dead stems in late winter to early spring.