Cape Ivy

Delairea odorata Lem.

Synonyms - Senecio mikanioides, Senecio mikanoides, Senecio scandens.

Family: Asteraceae

Names:

Odorata refers to its sweet fragrance when in flower or when crushed.
Cape Ivy because it comes from the Cape region of South Africa and it has Ivy like leaves.

Other Names:

Ivy Groundsel
German Ivy
Mile-a-minute because it grows so fast.

Summary:

A twining perennial vine with slender green or purple stems, yellow flowers without petals held above the foliage and alternate triangular-lobed leaves with ear like stipules. Each plant may be several metres in diameter and often forms a mat over underlying vegetation.

Description:

Cotyledons:

Two.

First leaves:

Leaves:

Flat, dull to glossy green and often purple tinged, limp, alternate. Fragrant when crushed.
Stipules - Kidney shaped and paired at the base of the petiole. About 5-10 mm wide. These may fall off with age.
Petiole - 20-90 mm long. Usually longer than the leaf.
Blade - Light green often with a purple tinge, fleshy. 30-100 mm long x 30-100 mm wide. Triangular to round in outline with 2-7 triangular lobes with broad shallow interspaces. Lobes at the base may be notched. 3-7 veins arranged in a finger like pattern. Often more silvery on the underside. Base indented. Sides lobed. Tip pointed. Hairless. Thin but somewhat fleshy.
Upper leaves smaller.

Stems:

Up to 3000-4000 mm long and usually less than 10 mm diameter. Fleshy, many branches usually but occasionally unbranched, twining and hairless. Sap not milky. Breaks easily.
Smooth and green or purplish and often striped when young becoming green to creamy-brown, warty and woody with age. Smooth and hairless.
May form roots at the nodes (stolons).

Flower head:

Loose branched arrangement of about 12-50 flower heads with a single flower head on the end of each bract carrying stalk (corymbose panicle) which are at the ends of the main branches and from leaf axils and held above the leaves. Involucre about 4 mm long x 2-2.5 mm diameter (expanding to 7 mm diameter).

Flowers:

Yellow. 10-12 florets in the head and all tubular, all bisexual, 8-12 mm long. Head 7 mm diameter when expanded with no "petals". Sweetly scented.
Ovary -
Style branches thread like and flat tipped (truncate), hairy at the tip.
Receptacle - Flattish, naked.
Petals - None.
Stamens -
Anthers - Obtuse at the base with sterile basal ears (auricles). Tailed
Bracts - 8-10, parallel sided, oblong, free, 3-5 mm long. 2-4 smaller outer bracts near the base.

Fruit:

Achene. Cylindrical, ribbed, smooth and almost hairless.

Seeds:

Reddish brown, 2 mm long, smooth and hairless
Tuft of silky white hairs (pappus), 4-6 mm long on top that break of easily.

Roots:

Shallow, fibrous or woody.

Key Characters:

Twining perennial.
Sap not milky.
Petiole present.
Leaves cordate-hastate, alternate.
Involucre cylindrical.
Involucre bracts, 8-9, all in one row, free, with a few small ones at the base.
Flowers yellow, twice as long as the involucre, all tubular, all bisexual.
Flower heads bisexual (homogamous), discoid.
No "petals".
Style branches truncate with a tuft of collecting hairs above the stigmatic lines.
Receptacle naked.
Pappus of fine silky hairs.
Adapted from John Black and Gwen Harden.

Biology:

Life cycle:

Perennial.
Seeds germinates in autumn, grow rapidly and is able to withstand drought by summer. It rarely flowers in the first year. Stems may take root where they contact the ground and flowering occurs in the second and subsequent years. Cut stems can survive for some months and take root when moisture is available.

Physiology:

Drought tolerant. Frost sensitive. Prefers full sun to part shade. Will tolerate moderate shade levels and salt laden winds.

Reproduction:

By seed, stolons and stem fragments.

Flowering times:

June to July in WA.
July to August in Victoria.
June to September in SA.
Mainly in winter in NSW.
May to October in New Zealand.

Seed Biology and Germination:

Rarely establishes from seed. Seed germinates in autumn.
Up to 40,000 seeds per plant per year.

Vegetative Propagules:

Stem fragments and stolons

Hybrids:

Allelopathy:

Population Dynamics and Dispersal:

Spread by seeds, stem fragments and stolons.
Spread by intentional planting, wind, water, dumping of garden refuse, slashing of firebreaks and movement of contaminated soil.
Seed is readily spread by wind.

Origin and History:

South Africa.

Distribution:

ACT, NSW, QLD, SA, TAS, VIC, WA.
Naturalised at Albany and the Swan Coastal Plain.
New Zealand.

Courtesy Australia's Virtual Herbarium.

Habitats:

Climate:

Warm temperate rainforest.
High rainfall, frost free areas.

Soil:

Prefers winter wet sandy-clay soils. Tolerates a wide variety of soils.

Plant Associations:

Heathland, woody heathland, sclerophyll forest, dry coastal, dunes and riparian vegetation. Forest margins.

Significance:

Beneficial:

Ornamental.
Used as a cover or screen for fences.

Detrimental:

Weed of disturbed bush that can smother vegetation to a few metres high.
Highly invasive forming dense stands that prevent recruitment of native plants.

Toxicity:

Toxic to stock causing liver damage after long and continuous consumption.

Symptoms:

Treatment:

Legislation:

Noxious weed of parts of NSW.
Pest plant of New Zealand.

Management and Control:

Avoid dumping garden refuse in bushland or moving soil from infested areas.
If removing manually, collect all stem fragments and burn because these can survive for many months if left on site.
Regular mowing provides control but tends to spread it to clean areas.
Avoid slashing firebreaks in infested areas.
Stems can be cut near the ground and hung in vegetation to dry. Stems with flowers should be destroyed as seed can be produced from reserves within the cut stems. Regular monitoring is required to remove stems that have taken root where they contact the ground and remove stem fragments that taken root.
Stems are usually too fragile to successfully use cut stump, frilling or scrape and paint methods of herbicide application

Thresholds:

Eradication strategies:

Spray with 500 mL/ha clopyralid (300 g/L) or 200 g/ha clopyralid (750 g/L) plus 0.25% wetting agent.
Spot spray with 10 mL clopyralid (300 g/L) or 4 g clopyralid (750 g/L) plus 25 mL wetting agent in 10 L water. Many woody native species will tolerate these levels of herbicide.
For vegetative plants growing on trees, these may be cut at waist height and the stems pulled away from the tree and then sprayed with 1:100 glyphosate.
Large infestations are difficult to remove manually because the stems tend to break and produce new infestations.
Small infestations can be removed by hand. Collect all stem fragments as these will take root if left on site. Burn collected stems.

Herbicide resistance:

None reported.

Biological Control:

None.

Related plants:

None in the same genus but many in the closely related Senecio genus

Plants of similar appearance:

Blue Periwinkle (Vinca major) has purple flowers.
Canary Creeper (Senecio tamoides)
Cape Ivy or Climbing Groundsel (Senecio angulatus) has yellow "petals", no stipules, and fleshier leaves, thicker and stiffer stems.
Clematis (Clematis linearifolia, Clematis pubescens) are native climbing vines have white flowers and the 3 leaflets have long stalks (petiolules) of similar length.
Dolichos Pea (Dipogon lignosus) has pea type flowers.
Ivy (Hedera species)
New Zealand Spinach (Tetragonia tetragonoides)
Sea Spinach (Tetragonia decumbens)
Wandering Jew (Tradescantia albiflora) has white flowers.

References:

Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia). P887

Bodkin, F. (1986). Encyclopaedia Botanica. (Angus and Robertson, Australia).

Blood, K. (2001). Environmental weeds: a field guide for SE Australia. (CH Jerram & Associates, Australia). P104-105. Photo.

Everist, S.L. (1974). Poisonous Plants of Australia. (Angus and Robertson, Sydney).

Harden, Gwen J. (1991). Flora of NSW. (Royal Botanic Gardens, Sydney). Volume . P. Diagram.

Hussey, B.M.J., Keighery, G.J., Cousens, R.D., Dodd, J. and Lloyd, S.G. (1997). Western Weeds. A guide to the weeds of Western Australia. (Plant Protection Society of Western Australia, Perth, Western Australia). P

Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne). P286. Photo.

Lazarides, M. and Cowley, K. and Hohnen, P. (1997). CSIRO handbook of Australian Weeds. (CSIRO, Melbourne). #331.1

Muyt, A. (2001). Bush Invaders of South-East Australia: a guide to the identification and control of environmental weeds found in South East Australia. (R.G and F.J. Richardson, Australia). P134. Photos.

Paczkowska, G. and Chapman, A. (2000). The Western Australia flora: a descriptive catalogue. (Wildflower Society of Western Australia (Inc), the Western Australian Herbarium, CALM and the Botanic Gardens & Parks Authority). P161.

Randall, J.M. and Marinelli, J. (1996) Invasive Plants. (Brooklyn Botanic Gardens Inc. Brooklyn). P. Photo.

Roy, B., Popay, I., Champion, P., James, T. and Rahman, A. (1998). An Illustrated Guide to Common Weeds of New Zealand. (New Zealand Plant Protection Society). P90. Photos.

Acknowledgments:

Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.