Rubus fruticosus 'Merton Thornless' (Blackberry 'Merton Thornless')

Botanical name

Rubus fruticosus 'Merton Thornless'

Other names

Blackberry 'Merton Thornless'

Genus

Rubus Rubus

Variety or Cultivar

'Merton Thornless' _ 'Merton Thornless' is a compact, deciduous shrub with long, thornless canes, white flowers in summer and medium-sized, dark blackberries in late summer and early autumn.

Foliage

Deciduous

Habit

Compact, Spreading

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Colour

Flower

White in Summer

Foliage

Dark-green in Spring; Dark-green in Summer; Pale-yellow, Pale-red in Autumn

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How to care

Watch out for

Pests

It is best to rotate crops to avoid pest and disease problems.

Specific pests

Aphids , Leafhoppers , Raspberry beetle , Raspberry leaf and bud mite

General care

Pruning

Prune old canes to ground level in late winter and tie in new canes.

Propagation methods

Layering

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Monthly care advice

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Where to grow

Rubus fruticosus 'Merton Thornless' (Blackberry 'Merton Thornless') will reach a height of 2.5m and a spread of 7m after 2-5 years.

Suggested uses

Add to salads, Banks and Slopes, Cake decoration, Containers, Cottage/Informal, Flavouring food and drinks, Hedging/Screens

Cultivation

Plant outdoors in summer in well-drained neutral soil against a fence or trellis. May not survive harsh, cold winters unless in a sheltered spot.

Soil type

Clay, Loamy, Sandy

Soil drainage

Moist but well-drained, Well-drained

Soil pH

Neutral

Light

Full Sun

Aspect

South, East, West

Exposure

Sheltered

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

Hardy (H4)

USDA zones

Zone 9, Zone 8, Zone 7, Zone 6, Zone 5

Defra's Risk register #1

Plant name

Rubus fruticosus 'Merton Thornless' (Blackberry 'Merton Thornless')

Common pest name

grape ground pearl

Scientific pest name

Margarodes vitis

Type

Insect

Current status in UK

Absent

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

2

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

5

General biosecurity comments

Main pathway; Vitis spp. plants for planting; already prohibited. However; further consideration of other pathways is required.

Defra's Risk register #2

Plant name

Rubus fruticosus 'Merton Thornless' (Blackberry 'Merton Thornless')

Common pest name

Apple root knot nematode

Scientific pest name

Meloidogyne mali

Type

Nematode

Current status in UK

Unknown

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

UK (along with certain other European countries) received potentially infested trees in 1992; but these were destroyed at the end of the trial period and targeted surveillance has failed to find any trace of the nematode. Main impacts are on elm; apple and mulberry and industry should source such material carefully.

Defra's Risk register #3

Plant name

Rubus fruticosus 'Merton Thornless' (Blackberry 'Merton Thornless')

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/