Alnus glutinosa (Common alder)

Botanical name

Alnus glutinosa

Other names

Black alder, European alder, Common alder, Aller

Genus

Alnus Alnus

Species

A. glutinosa - A. glutinosa is a medium, multi-stemmed tree with glossy green leaves and male catkins. It is suitable for damp or wet soil.

Foliage

Deciduous

Tree shape

Broadly conical

Colour

Flower

Brown in Spring

Foliage

Bright-green in Summer

How to care

Watch out for

Specific pests

Alder sucker , Leaf-mining sawflies

Specific diseases

Bark canker

General care

Propagation methods

Hardwood cuttings, Seed

Monthly care advice

Where to grow

Alnus glutinosa (Common alder) will reach a height of 15m and a spread of 8m after 20-50 years.

Suggested uses

Hedging/Screens, Low Maintenance, Wildlife, Foliage only

Cultivation

Thrives in poor, wet conditions.

Soil type

Chalky, Clay, Loamy

Soil drainage

Moist but well-drained, Well-drained

Soil pH

Acid, Alkaline, Neutral

Light

Full Sun

Aspect

North, South, East, West

Exposure

Exposed, Sheltered

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

Hardy (H4)

USDA zones

Zone 10, Zone 9, Zone 8

Defra's Risk register #1

Plant name

Alnus glutinosa (Common alder)

Common pest name

Scientific pest name

Melampsoridium hiratsukanum

Type

Fungus

Current status in UK

Present (Limited)

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

5

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

4

General biosecurity comments

Pathogen of alder; established in the UK and elsewhere.

Defra's Risk register #2

Plant name

Alnus glutinosa (Common alder)

Common pest name

Alder bleeding canker; Alder Phytophthora root disease

Scientific pest name

Phytophthora alni

Type

Oomycete

Current status in UK

Present (Widespread)

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

4

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

4

General biosecurity comments

Damaging pathogen of Alder; first detected in the UK in 1993; which has subsequently spread to most areas. Alders are important in the context of watercourse management. No prospect of eradication or containment but possible co-ordinated action to mitigate impacts to be considered with stakeholders.

Defra's Risk register #3

Plant name

Alnus glutinosa (Common alder)

Common pest name

Alfalfa dwarf; Anaheim disease; California vine disease; Dwarf disease of alfalfa; Dwarf disease of lucerne; Leaf scald of oleander; Leaf scald of plum; Leaf scorch; Phony disease of peach; Pierce's disease of grapevine; Variegated chlorosis of citrus

Scientific pest name

Xylella fastidiosa subsp. multiplex

Type

Bacterium

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)

4

General biosecurity comments

A bacterial disease with a wide host range detected in Corsica. Although EU regulated; there remains some concern about the risk of introduction. This subspecies is known to be able to thrive in cooler climates. Should an outbreak occur; there would be a need for eradication action which would result in environmental and social impacts.

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/