Rhododendron maximum (Great laurel )

Botanical name

Rhododendron maximum

Other names

Great laurel , American rosebay

Genus

Rhododendron Rhododendron

Species

R. maximum - R. maximum is an upright, open, multi-stemmed, often thicket-forming, evergreen shrub with large, leathery, strap-shaped, dark green leaves, reddish-brown beneath, and spherical clusters of pink or white flowers in early summer.

Native to

Eastern North America

Foliage

Evergreen

Habit

Open branches, Upright

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Colour

Flower

Pink, White in Summer

Foliage

Dark-green in All seasons

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How to care

Watch out for

Specific pests

Vine weevil , Leafhoppers , Caterpillars , Aphids

Specific diseases

Silver leaf , Rhododendron petal blight , Rhododendron bud blast , Powdery mildew

General care

Propagation methods

Semi-hardwood cuttings, Grafting, Layering

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Monthly care advice

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Where to grow

Rhododendron maximum (Great laurel ) will reach a height of 4.5m and a spread of 3.5m after 10-20 years.

Suggested uses

Containers, Wallside and trellises, Beds and borders, Cottage/Informal, Banks and Slopes

Cultivation

Plant in moist, humus-rich, free-draining, acid soil in sun or dappled shade. Plant shallowly. Protect from frost to prevent damage to flowers.

Soil type

Clay, Loamy, Sandy

Soil drainage

Well-drained, Moist but well-drained

Soil pH

Acid

Light

Partial Shade, Full Sun

Aspect

North, South, East, West

Exposure

Sheltered

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

Hardy (H4)

USDA zones

Zone 7, Zone 6, Zone 5, Zone 4, Zone 3

Defra's Risk register #1

Plant name

Rhododendron maximum (Great laurel )

Common pest name

Ramorum leaf blight; Ramorum shoot dieback; Rhododendron twig blight; Sudden oak death

Scientific pest name

Phytophthora ramorum

Type

Oomycete

Current status in UK

Present (Limited)

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

Pathogen of larch and other hosts subject to EU emergency legislation. A containment strategy is in place in the UK; reflecting its presence in wider environment/forestry settings in some areas. EU regulatory status is under review.

Defra's Risk register #2

Plant name

Rhododendron maximum (Great laurel )

Common pest name

leaf rust of blueberry

Scientific pest name

Thekopsora minima

Type

Fungus

Current status in UK

Absent

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

4

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

3

General biosecurity comments

Rust fungus affecting blueberry and hemlock. This fungus has been detected in Europe (Germany; Netherlands and Portugal). Some uncertainty about the suitability of UK native host species. But the case for regulation should be considered based on the EPPO PRA.

Defra's Risk register #3

Plant name

Rhododendron maximum (Great laurel )

Common pest name

pink wax scale; red was scale; ruby wax scale

Scientific pest name

Ceroplastes rubens

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

Based on its biology and low potential impact continued action on this pest in the UK would not be considered appropriate. It is likely to be of more concern to southern Member States of the EU; as it is an economic pest of citrus.

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/