Quick Facts

Quick facts

• Sweet Pittosporum (Pittosporum undulatum) is a large evergreen tree around 14 m tall with distinctive orange fruit.
• It is a native to eastern Australia, but has spread beyond its natural range through its use as a garden and street plant.
• It has also become a weed in its natural habitat due to altered fire regimes since European settlement.
• Seed is spread through garden waste, bird and animals droppings as well as attaching to fur and clothing.
• Sweet Pittosporum invades many habitats, shading out competition and altering soil nutrient loads.

What Does It Look Like?

What is it?

Sweet Pittosporum (Pittosporum undulatum) is a tall evergreen shrub or small tree and can attain heights of 25 m and a spread of up to about 12 m wide, but is normally smaller. Its foliage is very dense creating areas of deep shade beneath its canopy. Leaves are alternately arranged, or clustered at the end of branches with a leaf stalk 12–15 mm long. Leaves are ovate (shaped like a section through the long axis of an egg and attached by the wider end) to oval to narrowly obovate (shaped like a section through the long axis of an egg and attached by the narrow end), usually 6–17 cm long, 1.5–4 cm wide, shiny and dark green above, paler beneath, and have entire (lacking teeth) undulate margins (wavy edges) or occasionally flat (edges not wavy). The leaf tip is sharply to gradually pointed with new growth in winter and spring a lighter green.

Flowers are either male or female with plants either producing exclusively male or female flowers. The creamy white flowers are found in clusters of 4–5 at the end of stems. They are 1–2 cm long and bell-shaped with 5 petals, surrounded by a green calyx 0.6–1 cm long, divided to near midway also into 5 parts. Flowers are fragrant with a sweet scent. Male flowers with white, petals 1–2 cm long, narrower than in female flowers, anthers exerted from throat of flower. Female flowers 12–14 mm long, staminodes (infertile male organs) are present; stigma plump, capitate (club or knob shaped). 

The fruit is a capsule which is globose to ± obovate, 8–13 mm long, 10–15 mm diameter, hard and green, turning yellow then vivid orange. When ripe they split open revealing 20–30 sticky orange seeds, 3–4.5 mm long, brownish-red (Thorp & Wilson 1998 – ; Blood 2001; Harden 2007; PlantNET 2021; VicFlora 2016).

For further information and assistance with identification of Sweet Pittosporum contact the herbarium in your state or territory.

Flower colour

White

Growth form (weed type/habit)

Tree, Shrub

Where it currently grows? Preferred habitat

Sweet Pittosporum is very adaptable invading gardens, roadsides, coastal areas, healthland, grassland, woodland, wet and dry sclerophyll forests, rainforest as well as temperate, subtropical and tropical zones. It is most problematic in areas with greater than 700 mm rainfall (Blood 2001; Muyt 2001; Navie 2004).

Are there similar species?

Sweet Pittosporum is similar to other native species such as Diamond-leaved Pittosporum (Auranticarpa rhombifolia) and Brush Muttonwood (Myrsine howittiana). Diamond-leaved Pittosporum has leaved with toothed margins and relatively small white flowers (6-8 mm long), whereas Sweet Pittosporums has smooth-edged leaves and relatively large creamy white flowers (10-20 mm long). Brush Muttonwood has similar leaves and flowers to Sweet Pittosporum, but can be distinguished by its relatively small blue or purplish berries that do not split open when mature. In comparison Sweet Pittosporum has larger orange berries which do split open. Sweet Pittosporum also hybridises with Banyalla (Pittosporum bicolor), producing a hybrid weed that is difficult to distinguish from Sweet Pittosporum (Blood 2001; Navie 2004).

Why Is It A Weed?

What are its impacts?

Sweet Pittosporum is widely planted as a hardy garden shrub and used for hedges, windbreaks and firewood far beyond its original range. It has a high seed production, producing dense crops of seedlings. It can that rapidly colonies and invade open or disturbed habitats including native and roadside vegetation, forming dense thickets. with foliage that effectively shades out vegetation beneath the canopy. 

Agriculture: Not known to cause a problem in agricultural crops, pastures or Rangelands. 

Native ecosystems: Sweet Pittosporum is invasive in forests and bushland outside its natural range with foliage that effectively shades out vegetation beneath the canopy, and competes and changes in soil nutrients due to their nutrient rich leaf litter. This has effects on ground flora and has contributed to changes in native lizard and bird populations. Changes to fire regimes have allowed it to out-compete fire-adapted species and change fuel loads, even though it is fire-sensitive (Thorp & Wilson 1998 -; Blood 2001; Groves et al. 2005; Tamar Valley Weed Strategy undated). Sweet Pittosporum invasion has been particularly severe in dry sclerophyll forest remnants where natural fire regimes have been altered.

How does it spread?

Sweet Pittosporum reproduces by seeds and suckers. Spread has been encouraged by gardeners who praise its hardiness and sweet perfume. Seeds are dispersed by fruit eating birds and other animals including foxes and possums. It also spreads in dumped garden waste and contaminated soil and seeds stick to animals and footwear (Thorp & Wilson 1998 -; Blood 2001; Groves et al. 2005).

What is its history in Australia?

Sweet Pittosporum is a native of Australia that has become a weed outside its natural habitat due to its popularity as a garden plant (Thorp & Wilson 1998 -).

How To Manage It?

Best practice management

Non-chemical control: Seedling and small shrubs of Sweet Pittosporum can be removed by hand pulling or grubbing, taking care to remove the majority of the root system. Sweet Pittosporum can form a dense seed bank in the soil, with seeds germinating in response to removal of the parent trees. However, the seed is probably not long lived, surviving less than 5 years in the soil (Government pd South Australia 2021). If gradual removal over several or more years is the only option then strategically removing male or female plants may help prevent seed set could help.

Fire: Fire can help control some infestation, however low intensity burns will not kill plants and are likely to promote vigorous re-shooting. Fires may also negatively impact on other plants, especially in wet environments. It is not recommended to remove large areas of Sweet Pittosporum within its natural range (Muyt 2001; Tamar Valley Weed Strategy undated).

Chemical control: Herbicide is best for larger trees and can either be applied to the stump of a recently felled tree or injected into the stems or trunk. Follow up treatment should be carried out as plants can reshoot. 

Please see the Australian Pesticides and Veterinary Medicines Authority for chemical information http://www.apvma.gov.au

Does it have a biological control agent?

NO

When does it grow? (lifecycle/growth calendar)

Sweet Pittosporum flowers in early spring, fruiting in autumn to winter. Seeds sometimes germinate after seed fall in spring, but most germinate in autumn. Seed production is high. First flowering occurs when the plants are 4–5 years old and they are apt at establishing under existing trees due to their tolerance of shade. Fresh seed has a viability of over 90%, with viability declining with age (Blood 2001).

Where Is It Found?

Which states and territories is it found?

ACT, NSW, QLD, SA, TAS, VIC, WA

What areas within states and territories is it found?

Sweet Pittosporum is native to coastal areas of southern Queensland, New South Wales and Victoria. It is now a weed problem both within and outside its natural range in Victoria, South Australia, Tasmania and Western Australia. It is present on King, Lord Howe and Norfolk Islands and many countries overseas including Jamaica, the Azores and South Africa. It is already a serious weed in the Sydney area and the New South Wales mid-north coast (Thorp & Wilson 1998 – ; Navie 2004; VicFlora 2016).

Where does it originate?

Sweet Pittosporum is native to wet forests in coastal areas between the Great Dividing Range and the coast from southern Victoria to southern Queensland (Thorp & Wilson 1998 -).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

NO

Where is it a declared weed?

NSW, WA

Government weed strategies and lists – Weeds Australia

Is it on the National Alert List for Environmental Weeds?

NO

Government weed strategies and lists – Weeds Australia

Is it on the Agricultural Sleeper List?

NO

Government weed strategies and lists – Weeds Australia

Names And Taxonomy

Main scientific name

Pittosporum undulatum

Other scientific names (synonyms)?

Pittosporum undulatum Vent. subsp. undulatum

Does it have other known common name(s)?

Snowdrop Tree, Engraver Wood, Mock Orange, Native Laurel, Wave Leaved Pittosporum, White Holly, Native Daphne, Victorian Box, Australian Cheesewood, New Zealand Daphne, Victorian Laurel, Wild Coffee