Delairea odorata

This vigorous climbing perennial has a twinning purplish succulent stems and forms a dense cover. It has fleshy light green lobed leaves and the dense  yellow flower heads appear during winter.

Delairea odorata Lem. is naturally found from the East Cape to Port Elizabeth in South Africa growing in moist positions along forest margins or hillside grasslands shrubland and on disturbed soil from sea level to an altitude of 2500 m (8,202 ft) in Hawaii. It has also naturalised in many countries including Australia, New Zealand, Hawaii and the USA where it is regarded as an environmental weed. It prefers well drained to boggy fertile moist organic rich sandy to loamy soil with a pH range from 6.0 to 7.5 but is adaptable. It grows in an open sunny to semi-shaded position and is frost tender but drought and salt laden wind tolerant.

Cape Ivy is grown for its foliage and its vigorous spreading or climbing habit. It was originally cultivated as an ornamental growing over trellises for screening or used as a ground cover on embankments. It is now discouraged from use as it is invasive and is regarded as a weed. It is suitable for coastal and low mountain regions toleranting a wide range of habitats from rainforest to Mediterranean climates. It establishes in one season and forms a dense cover over shrubs and trees. It has a high water requirement once established. (Scale: 3-drops from 3) but is tolerant of dry conditions.

I.D. 871

UK hardiness zone H1b

Climate zones H1, 14 - 24

USDA Zone 9-10

Delairea (del-AER-ee-a) odorata (õ-do-RAY-ta)

Etymology

Genus: - Delairea – meaning unknown

Species:  Latin - odorata – meaning (fragrant, perfumed) referring to the flowers

Weed Potential

As a weed Cape Ivy is wide spread in high rainfall areas of Australia and is highly invasive growing in a variety of native habitats including woodlands, forests or dunes and along water courses. It also occurs in disturbed soils and neglected landscapes.

Growth occurs during the warmer months and the plant smothers the ground and climbs into the lower canopy cutting out the light for the host. The vine matures in 2-years preferring an open sunny position with moist soils. It can produce over 30,000 seeds yearly and the stem fragments can also form new plants. It tolerates salt laden winds or drier conditions once established commonly appear in bushland margins. The seed is dispersed by water or wind and in garden waste.

Control methods include physically digging out small infestations including the roots or the vine may be severed at the base and the foliage left in the canopy to dry out if no seeds are seen. Fruiting stems should be cut and bagged where possible then all plant material should be removed off site and destroyed.

Plants may also be sprayed with a non-selective herbicide taking care not to spray the native vegetation. Follow up applications are required as seeds mature on sprayed plants. Best to apply chemical sprays before flowers appear as the seeds form with in 4 to 8 weeks.

Asteraceae (ass-ter-AY-see-ee)        

(Compositae)

Sunflower Family

This family is recognised by several features the florets are clustered in the flower head, inferior ovary has one basal ovule and the stamens are connate around the style.

Distribution

This family is found throughout the world except Antarctica. In Australia they are found in arid and semi-arid regions covering large areas.

Diagnostic Features

There are numerous growth forms from small annual herbs, ephemeral, biennial or perennial rosette plants, shrubs but rarely creepers.

The leaves do not have stipules and may be arranged opposite or alternate with margins that are entire to deeply lobed. The texture may be leathery or succulent and may be reduced to spins or needles.

The simple flower is in a tight inflorescence with many florets that sit on a fleshy receptacle that is surrounded by many involucral bracts. In some genera the bracts are reduced or not present and the receptacle may be in an elongated form giving it a club-shape inflorescence.

Each flower has an inferior ovary normally with a colourful corolla on top with the calyx reduced to scales, bristle or hairs around the corolla.

Three distinctive Floret Types

1. Disk florets are funnel form corolla tube that has five equal lobes with fertile stamens and ovary.

2. The ligulate florets with a corolla that is split down one side and the limb formed is extended to form showy ray florets. These flowers are unisexual.

3. The filiform florets come from disk florets when the corolla tube is a slim cylindrical shape and these are normally unisexual.

The fruit produced from the different types is normally a cypsela (type of achene) although some florets don't produce fruit.

The corolla has five petals, which are five lobes in disk florets but are not easily seen in other types.

The stamens are arranged alternate with the petals and the filaments are normally fused to the corolla tube with the anthers arranged around the style in a connate form.

When the pollen falls onto the closed stigma the style elongates above the stamens and then the stigma opens to be pollinated.

The ovary is inferior with one chamber and one ovule and forms a one seeded fruit, which is really an indehiscent fruit (cypsela). These are normally distributed by animals with barbs formed by the pappus and some by wind.

Note:

This is one of the largest families but with low economic importance. They are used in the horticulture industry largely for cut flowers and in the case of sunflowers for seed oil. Many species are grown in domestic gardens and many have become weeds that are wide spread throughout the world.

This plant tolerates between USDA zones 9a to 10a and grows to 4 m (12 ft)

Fahrenheit         20º to 30º F

These temperatures represent the lowest average.

Celsius             -6.6º to -1.1º C

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