Delairea odorata (Cape ivy) - Invasive Plants in Portugal

Delairea odorata (Cape ivy)
Broad leaved climber, leaves with angular contour, and small yellow flowers.
Scientific name: Delairea odorata Lem.
Common names: Cape ivy, German ivy
Family: Asteraceae (Compositae)
Status in Portugal: invasive species
Risk Assessment score: (in development)
Synonymy: Senecio mikanioides Otto ex Walpers
Last update: 08/07/2014
How to recognise
Climbing herb, woody on the base, up to 5 m.
Leaves: semi-fleshy, from deltoid to orbicular,
lustrous, with a cordate blade on the base and with
3-5 acute lobes on each surface, giving them an
angular look; petiole with two small auricles on the
base.
Flowers: yellow and tubular, arranged in capitula,
which in turn are arranged in dense, axillary
panicles.
Fruits: cypselas 2-2,5 mm long, that has a pappus
with white hairs.
Flowering: December to February.
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Deltoid and lustrous leaves, with 3-5 lobes on each surface, giving them an angular look
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Delairea odorata (Cape ivy)
Similar species
It can be grossly mistaken with Bryonia cretica L. when flowers are not visible. However, the indentation
of the leaves of Delairea odorata is more acute and regular. When in flowering, it is completely different,
once B. cretica has white flowers.
Characteristics that aid invasion
It reproduces by seed, producing a high amount of seeds.
It also propagates vegetatively, by stem fragments that easily detach, root and originate new plants.
ORIGIN AND DISTRIBUTION
Native distribution area
South Africa (Cape region).
Distribution in Portugal
Mainland Portugal (Minho, Douro Litoral, Beira
Litoral, Estremadura), Azores archipelago (islands
of São Miguel, Santa Maria, Terceira, Graciosa, São
Jorge, Pico, Faial), Madeira archipelago (island of
Madeira).
Other places where the species is invasive
Australia, New Zealand, west USA (California),
Asian Southwest, several countries in western
Europe.
Introduction reasons
For ornamental purposes.
Preferential invasion environments
It frequently invades banks of watercourses, hedgerows and slopes, ruderal environments and
communities of thorny shrubs.
It also proliferates vigorously in gardened areas where it was initially planted.
IMPACTS
Impacts on ecosystems
It forms impenetrable mats that smother the trees, shrubs and grasses of other species, leading to their
death and preventing the development of native vegetation.
It also proliferates vigorously in gardened areas where it was initially planted.
Other impacts
All the parts of the plants are toxic, therefore being noxious for animals.
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Delairea odorata (Cape ivy)
CONTROL
Controlling an invasive species demands a well-planned management, which includes the determination
of the invaded area, identifying the causes of invasion, assessing the impacts, defining the intervention
priorities, selecting the adequate control methodologies and their application. Afterwards it is
fundamental to monitor the efficiency of the methodologies and recuperation of the intervened area as
to perform, whenever necessary, the follow-up control.
The control methodologies used for Delairea odorata include:
Physical control
Hand pulling (preferential methodology). In more compact substrates, hand pulling should be made
during the rainy season to facilitate the removal of the root system. It should be guaranteed that there
are no large fragments left in the ground, which root easily and originate new invasion foci. All pulled
material should be removed from the location for posterior destruction.
Physical + chemical control
Cut stump method. Cut the stems as close to the ground possible and apply herbicide a few seconds
afterwards (active substance: glyphosate, triclopyr) to the cut surface. Some authors refer that the
sprouts are more sensitive to herbicides, so alternatively, the application of herbicide may be made over
the sprouts.
Chemical control
Foliar application of herbicide: applied in extensive areas that are invaded by the species. Spray with
herbicide (active substance: glyphosate, triclopyr) limiting its application to the target species.
For additional information, visit the webpage www.invasoras.pt and/or contact us at [email protected].
REFERENCES
CABI (2012) Delairea odorata. In: Invasive Species Compendium. CAB International, Wallingford, UK. Available: www.cabi.org/
isc [Retrieved 12/11/2012].
Jardim R, Silva L, Gallo AG (2008) Delairea odorata Lem. In: Silva L, Land EO, Luengo JLR (eds) Flora e fauna terrestre invasora
na Macaronésia. Top 100 nos Açores, Madeira e Canárias. Arena, Ponta Delgada, pp. 248-250.
Marchante E, Freitas H, Marchante H (2008) Guia prático para a identificação de plantas invasoras de Portugal Continental.
Imprensa da Universidade de Coimbra, Coimbra, 183pp.
USDA, NRCS. (2012) The PLANTS Database. National Plant Data Team, Greensboro, NC 27401-4901 USA. Available: http://
plants.usda.gov [Retrieved 12/11/2012].
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