Quick Facts

Quick facts

• Fragrant Thunbergia (Thunbergia fragrans) is a native of India, Sri Lanka and China.
• It is a herbaceous twiner with quadrangular stems and white flowers.
• It can be found on the edges of rainforests, often twining in grasses or other vegetation.
• Fragrant Thunbergia can climb on and smother native plant species and is a potential major threat to the Wet Tropics.
• It is dispersed by seed, and by root and stem fragments establishing from dumped garden waste.

What Does It Look Like?

What is it?

Fragrant Thunbergia (Thunbergia fragrans) is a herbaceous twining plant with square stems in cross-section. The egg-shaped leaves are in opposite pairs with stalks (petioles) up to 4 cm long. The leaf blades are up to 10 cm long and 5 cm wide, with a heart shaped or arrow shaped base, somewhat irregularly toothed edges and a sharply pointed tip.

One or two white flowers form in each leaf axil (angle between leaf and stem). The flowers are on thick stalks (pedicels) 5-15 cm long with the tube of the flower encased by 2 leafy egg-shaped bracts (modified leaves), each up to 2 cm long. The narrow flower tube just exceeds the bracts in length. The flower has five lobes, each of which is about 2 cm long.

The fruit is an almost-rounded (sub-globose) capsule topped with a long, thick, beak. (Barker 1986; Navie 2004).

For further information and assistance with identification of Fragrant Thunbergia, contact the herbarium in your state or territory.

Flower colour

White

Growth form (weed type/habit)

Vine

Where it currently grows? Preferred habitat

Fragrant Thunbergia is usually found on the edges of rainforest, often twining in grasses or in roadside vegetation (Barker 2008 pers. comm.). It has the potential to be a weed of closed forests, forest margins, watercourses (i.e. riparian areas), urban bushland, disturbed sites, roadsides and plantation crops in tropical and sub-tropical regions (Weeds of Australia 2016).

Are there similar species?

While Fragrant Thunbergia is very similar to the native plant, Thunbergia arnhemica, this latter species may actually prove to be the same species as T. fragrans as they are virtually indistinguishable in appearance (Barker 2008 pers. comm.).

Fragrant Thunbergia is also similar to the climbers T. grandiflora, T. laurifolia (Blue Trumpet Vines), and T. alata (Black-eyed Susan), but its flowers are entirely white, whereas the latter three species have blue to purple (T. grandiflora and T. laurifolia), or orange and black flowers (T. alata) (Navie 2004).

Why Is It A Weed?

What are its impacts?

Native ecosystems: Although Fragrant Thunbergia is not currently problematic in Australia, in other countries it occurs as a weed of roadsides where it can form dense thickets and invade rainforests. It can climb on and smother native plant species, and is a potential major problem of native vegetation in the Wet Topics (Land Protection 2003).

How does it spread?

Dispersal in Fragrant Thunbergia is by seed, and by root and stem fragments (Navie 2004; PIER 2006). Due to its use as a garden ornamental plant, its dispersal can be facilitated by movement of plant fragments in dumped garden waste (Navie 2004).

What is its history in Australia?

Whether Fragrant Thunbergia has arrived in Australia or is a native plant is not known (Barker 2008 pers. comm.).

How To Manage It?

Best practice management

Chemical control: Some selectively applied herbicides used as foliar sprays are highly effective in controlling Thunbergia species (Land Protection 2003).

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

Non-chemical control: Mechanical control: Mechanical removal of Fragrant Thunbergia can reduce the problems associated with it smothering native vegetation, but it can quickly regrow from tuberous roots (with underground storage organs). Physical control: Smaller plants can be dug out, but larger more established populations are more difficult to control using this method, and therefore spraying or injecting with herbicides is often the only viable option.

Does it have a biological control agent?

NO

When does it grow? (lifecycle/growth calendar)

Fragrant Thunbergia flowers between January and April (i.e. during the wet season) (Barker 2008 pers. comm.). Thunbergia species are perennial, living for many years (Land Protection 2003).

Where Is It Found?

Which states and territories is it found?

QLD

What areas within states and territories is it found?

Fragrant Thunbergia has been recorded from some locations in Queensland. It is virtually impossible to distinguish from T. arnhemica which makes working out its current distribution difficult (Barker 2008 pers. comm.).

Where does it originate?

Originally described from Indian material in the 1800s, Fragrant Thunbergia is generally thought to be native to India, Sri Lanka and China (e.g. Navie 2004). However, plants very similar to Fragrant Thunbergia are found from India through to Australia, and despite their having been given 35 different names (Bremekamp 1955) it is quite possible that this is really a single variable species (Barker 2008 pers. comm.).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

NO

Where is it a declared weed?

QLD, 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

Thunbergia fragrans

Other scientific names (synonyms)?

Flemingia grandiflora Roxb. ex Rottler

Does it have other known common name(s)?

Sweet Clockvine, White Clockvine, White Lady, White Thunbergia