Pittosporum

Pittosporum undulatum Vent.

Synonyms -

Family: Pittosporaceae

Names:

Pittosporum from the Greek pitta meaning pitch and spora meaning seed and refers to the sticky pulp around the seed.
Undulatum refers to the wavy or undulating margins of the leaves.

Other Names:

Sweet Pittosporum

Summary:

Pittosporum (Pittosporum undulatum) is a perennial, small bushy tree to 8 m high. The leaves are elliptic, 60-150 mm long and 15-40 mm wide, darker green on the upper surface and with somewhat wavy margins. The clustered flowers are bell-shaped, sweetly scented and white to cream in colour. The sepals are 6-10 mm long and hairy, the petals are 10-20 mm long. The fruits of Pittosporum are orange, hard, globular capsules which open to release brown seeds surrounded by a sticky pulp. Native to south eastern Australia, it is an ornamental that was often used as a hedge plant and is now invading gullies, forest and woodland areas of high rainfall regions. It flowers from October to November.

Description:

Cotyledons:

Two.

First leaves:

Leaves:

Alternate or clustered at the ends of branches.
Stipules -
Petiole - 12-15 mm long.
Blade - 60-150 mm long x 15-40 mm wide, oval to lance or egg shaped, dark green on top and paler underneath, usually with wavy edges but may be flat. Tip pointed. Sides curved and undulating. Base tapered. Mature leaves hairless, young leaves may have a few hairs.

Stems:

Up to 8 m tall. Woody, branched. Hairless. apart from a few hairs on young growth.
Sapwood is diffuse porous.

Flower head:

Clusters of flowers at the ends of branches.

Flowers:

Fragrant. Bell shaped.
Ovary - Superior, almost 2-5 celled by the intrusion of partial placentas. Hairy.
Style - short, simple.
Stigma - capitate.
Sepals - 6-10 mm long, maybe hairy on the outside, narrowly egg shaped.
Petals - Egg shaped, 10-12 mm long, creamy white, united near the base with a spreading limb.
Stamens - slender filaments.
Anthers - Ovate to oblong, opening by a lengthwise split. Shorter than filaments.

Fruit:

Orange to yellow brown, globular to almost pear shaped, smooth, hard, thick capsule 10-14 mm long x 10 mm diameter with many seeds. Sparsely hairy or hairy when young and becoming hairless with age.
Hard and opens by valves.

Seeds:

Brown to red brown, globular often in a sticky pulp. Not winged.

Roots:

Key Characters:

Shrub or tree >1 m tall.
Branchlets lacking spines.
Leaves simple, alternate, not aromatic, no glands, >15 mm wide and >22 mm long.
Mature leaves glabrous on both surfaces, margins entire and usually distinctly undulate.
White to cream regular flowers.
Ovary superior and sessile.
Anthers on slender filaments, ovate or oblong opening by a longitudinal split.
Anthers shorter than filaments.
Petals mainly free but united at the base, <20 mm long, glabrous on the outer surface.
Orange, thick and hard or leathery capsules usually >10 mm long.
Seeds not winged, viscid.
Adapted from G. Harden

Biology:

Life cycle:

Often germinates in abundance after fire or disturbance and grows quickly to dominate other species. Trees produce their first seed when about 5 years old.

Physiology:

Reproduction:

By seed.

Flowering times:

October to November or spring in WA.
Spring in NSW.

Seed Biology and Germination:

Vegetative Propagules:

Stems coppice when cut.

Hybrids:

Hybridises with Pittosporum revolutum and Pittosporum bicolor.

Allelopathy:

Population Dynamics and Dispersal:

Aggressively spreads after fire or disturbance. Seeds are spread by birds and mammals. Seeds have a short to medium longevity in the soil.

Origin and History:

Native plant of south eastern Australia.
Introduced in South Australia, Tasmania and Western Australia.

Distribution:

ACT, NSW, QLD, SA, TAS, VIC, WA.
Lord Howe Island and South Africa.

Courtesy Australia's Virtual Herbarium.

Habitats:

Rainforest, wet sclerophyll forest and sheltered areas in dry sclerophyll forest and woodlands

Climate:

More invasive in high rainfall areas.

Soil:

Prefers granite derived soils

Plant Associations:

Significance:

Beneficial:

Ornamental and used as a hedge plant.
Used for gums.

Detrimental:

Aggressive invader of bushland and disturbed areas especially after fire.

Toxicity:

Not recorded as toxic, but fruits may contain a saponin which may cause dopiness.

Symptoms:

Treatment:

Remove stock from infested area.

Legislation:

None.

Management and Control:

Avoid burning areas that have a Pittosporum seed bank.
Control seedlings after fire by wiping with 1 part glyphosate(360g/L) in 2 parts water.
Paint lower 50 cm of trunk with a mixture of 100 mL Access® in 6 L of diesel, or fell tree and apply this mixture or neat glyphosate(360g/L) immediately to the cut stump.

Thresholds:

Eradication strategies:

Avoid burning areas that have a Pittosporum seed bank unless control of seedlings is planned for the following seasons. Control seedlings after fire by wiping with 1 part glyphosate(360g/L) in 2 parts water.
Paint lower 50 cm of trunk of trees with a mixture of 100 mL Access® in 6 L of diesel, or fell the tree and apply this mixture or neat glyphosate(360g/L) immediately to the cut stump. Trees will reshoot freely from the stump after felling if the stump is not removed or treated with herbicide.
Fell or bulldoze, then burn thickets. Control seedlings and sprouting by wick application of glyphosate.
Replant species that will produce a dense understorey.

Herbicide resistance:

None reported.

Biological Control:

Unlikely because Pittosporum is an Australian native plant and there are many closely related native species.

Related plants:

There are 26 native Pittosporum species in WA.
The WA native species of Pittosporum (Pittosporum phylliraeoides) has narrower leaves at 6-16 mm wide, smaller flowers and small sepals at 1.5-3.5 mm long which are hairless apart from their margins, smaller petals at 7-12 mm long and orange to red heart-shaped capsules.
Introduced weedy species include
Pittosporum crassifolium
Pittosporum eugenioides
Pittosporum moluccanum
Pittosporum tenuifolium is an ornamental hedge plant.

Plants of similar appearance:

Eucalypts and Acacias don't have white petalled flowers and usually don't have wavy leaves.
Castor Oil Plant (Ricinus communis) differs in its very large and deeply lobed leaves to 400 mm across, its red female flowers and yellow male flowers and spiny fruit.
Kangaroo Apple (Solanum laciniatum) differs in its deeply divided leaves and purple-blue flowers and soft fruit.

References:

Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia). P394.

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

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

Harden, Gwen J. (1991). Flora of NSW. (Royal Botanic Gardens, Sydney). Volume 3. P72. 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). P196. Photo.

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

Lazarides, M. and Cowley, K. and Hohnen, P. (1997). CSIRO handbook of Australian Weeds. (CSIRO, Melbourne). #792.5.

Moore, J.H. and Wheeler, J.R. (2008). Southern Weeds and their Control. (Second Edition). Department of Agriculture and Food Western Australia. P196-197. Photos.

Wheeler, Judy, Marchant, Neville and Lewington, Margaret. (2002). Flora of the South West: Bunbury - Augusta - Denmark. (Western Australian Herbarium, Bentley, Western Australia). P794. Diagram.

Acknowledgments:

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