Quick Facts

Quick facts

• Small-flower Gaura (Oenothera curtiflora) is a North American native plant that is an annual herb, with pink flowers, that grows to about 1 m in height.
• It is very drought tolerant and has the potential to become an environmental weed.
• It has been planted in gardens and is spreading from seed into surrounding bushland areas.
• It is no longer legal to propagate or sell this species in New South Wales and Western Australia.

What Does It Look Like?

What is it?

Small-flower Gaura (Oenothera curtiflora) is an annual herb (a plant that completes its life-cycle and dies within one year) which grows to about 1 m in height. The stems are mostly unbranched, erect and softly hairy. The leaves are egg-shaped to oval, 2–12.5 cm long and 0.5–4 cm wide. Their margins are wavy and minutely toothed.

The flowers are arranged in a dense inflorescence (flower structures) up to 40 cm long and 1 cm wide. They open near sunset and fade by the morning. The petals are pink and 2–3 mm long.

The fruit is ridged, and about 10 mm long and 2 mm wide (Harden 2007).

For further information and assistance with identification of Small-flower Gaura contact the herbarium in your state or territory.

Flower colour

Pink

Growth form (weed type/habit)

Herb

Where it currently grows? Preferred habitat

In Australia, Small-flower Gaura is located particularly along creeks and roadsides (Southern Tablelands and South Coast Noxious Plants Committee undated; SGA undated).

Are there similar species?

Two species of Oenothera [as Gaura] are naturalised in Australia. Small-flower Gaura is softly hairy with symmetrical flowers and petals less than 2 mm long. The other species, also known as Clockweed or Butterfly Bush Oenothera lindheimeri [as Gaura lindheimeri], is larger and coarsely hairy, and has asymmetrical flowers with protruding stamens and style and petals longer than 2 mm (Western Australian Herbarium 1998; Southern Tablelands and South Coast Noxious Plants Committee undated).

Why Is It A Weed?

What are its impacts?

Native ecosystems: Small-flower Gaura is a garden escape that has become an invasive environmental weed in a few locations particularly along roadsides, creeks and waterways (NSW WeedWise 2018).

Agriculture: In the United States of America it grows in cultivated fields, pastures, waste places and stream banks (Jepson Interchange 1993).

How does it spread?

Small-flower Gaura produces fine seed which is spread by wind (Southern Tablelands and South Coast Noxious Plants Committee undated).

What is its history in Australia?

Small-flower Gaura has been grown in many gardens around Australia, and has become an occasional garden escapee (SGA undated).

How To Manage It?

Best practice management

Non-chemical control: to prevent Small-flower Gaura from seeding it is important to cut the plant right back after flowering (SGA undated).

Chemical control: Herbicides can be used to control Small-flower Gaura (NSW WeedWise 2018).

Does it have a biological control agent?

NO

When does it grow? (lifecycle/growth calendar)

Small-flower Gaura is an annual plant that flowers in summer (Harden 2007).

Where Is It Found?

Which states and territories is it found?

NSW, QLD, VIC

What areas within states and territories is it found?

Small-flower Gaura grows in New South Wales in the Kyogle and Gunnedah district (Harden 2007). It has been found on the Victorian-New South Wales border and in south-eastern Queensland (AVH 2007).

Where does it originate?

Small-flower Gaura is native to central United States of America and Northern Mexico (Jepson Interchange 1993).

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

Oenothera curtiflora

Other scientific names (synonyms)?

• Gaura parviflora Douglas ex Hook.
• Gaura parviflora Douglas ex Lehm.

Does it have other known common name(s)?

Clock-weed, Clockweed, Velvetweed, Velvety Gaura, Downy Gauraeed