Agastache 'Black Adder' (Giant hyssop 'Black Adder')

Botanical name

Agastache 'Black Adder'

Other names

Giant hyssop 'Black Adder', Anise hyssop 'Black Adder', Hummingbird mint 'Black Adder'

Genus

Agastache Agastache

Variety or Cultivar

'Black Adder' _ 'Black Adder' is a bushy, clump-forming perennial with veined, glossy, lance-shaped, mid- to dark green, aromatic leaves and dense spikes of violet-blue and dark purple flowers from midsummer into autumn.

Foliage

Deciduous

Fragrance

Aromatic leaves

Habit

Bushy, Clump-forming, Upright

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Colour

Flower

Dark-purple, Blue, Violet in Summer; Violet, Dark-purple, Blue in Autumn

Foliage

Dark-green in Spring; Dark-green in Summer; Dark-green in Autumn

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How to care

Watch out for

Specific diseases

Crown rot , Leaf spot , Powdery mildew , Rust

General care

Pruning

Cut back the faded flower-stems in autumn or leave for winter interest and cut back in spring. In colder areas, leave leaf and flower stems for winter protection and cut back in late winter or early spring.

Propagation

A sterile cultivar so will not set viable seed.

Propagation methods

Division, Semi-ripe cuttings

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Monthly care advice

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Where to grow

Agastache 'Black Adder' (Giant hyssop 'Black Adder') will reach a height of 0.75m and a spread of 0.5m after 1-2 years.

Suggested uses

Beds and borders, City, Cottage/Informal, Garden edging, Gravel, Ground Cover

Cultivation

Plant in fertile, well-drained soil in full sun. Prefers alkaline soil but will tolerate poor, acid conditions.

Soil type

Chalky, Loamy, Sandy

Soil drainage

Moist but well-drained, Well-drained

Soil pH

Acid, Alkaline, Neutral

Light

Full Sun

Aspect

South, West

Exposure

Exposed, Sheltered

UK hardiness Note: We are working to update our ratings. Thanks for your patience.

Hardy (H4), Tender in frost (H3)

USDA zones

Zone 9, Zone 8, Zone 7, Zone 6

Defra's Risk register #1

Plant name

Agastache 'Black Adder' (Giant hyssop 'Black Adder')

Common pest name

tomato thrips

Scientific pest name

Ceratothripoides brunneus

Type

Insect

Current status in UK

Absent

Likelihood to spread to UK (1 is very low - 5 is very high)

3

Impact (1 is very low - 5 is very high)

3

General biosecurity comments

Thrips present in Africa; the Caribbean and parts of Asia; frequently intercepted in the UK. Can cause significant damage to tomatoes and other crops in countries where it is present. Europe wide PRA will consider its potential to establish and cause damage.

About this section

Our plants are under greater threat than ever before. There is increasing movement of plants and other material traded from an increasing variety of sources. This increases the chances of exotic pests arriving with imported goods and travellers, as well as by natural means. Shoot is working with Defra to help members to do their part in preventing the introduction and spread of invasive risks.

Traveling or importing plants? Please read "Don't risk it" advice here

Suspected outbreak? Click here for contact details to report to the relevant authority.

Date updated: 7^th March 2019 For more information visit: https://planthealthportal.defra.gov.uk/