Impatiens sodenii

Shrub balsam

Family: Balsaminaceae

Origin: Africa

Close up of shrub basalm flowers.
Originating from Africa this is also known as Shrub Impatiens. Stems remain soft and can grow up to 2m tall.
Photo credit: Jonathan Boow

Regional Pest Management Plan (RPMP) status

  • Not a legally declared pest

View more about the RPMP statuses

General description

Erect perennial shrub < 2 m tall. Stems are hairless and semi-succulent. Leaves are < 12 x 3.5 cm, lanceolate, toothed and borne in whorls. Flowers are pale pink/white, have a long, thin spur and are borne year-round. Fruits are smooth and green.

What you need to know

Although shrub balsam is not a legally declared pest plant, it may still be invasive in some situations. Consider lower risk alternatives for your garden, such as native plants.

Habitats

Coastal areas, disturbed forests, forest margins, scrubland, wasteland, gardens, urban areas.

Dispersal

Seeds dispersed by explosive dehiscence. Vegetative spread from layering and stem fragments, dispersed by water. Human-mediated dispersal through dumping of garden waste and deliberate plantings.

Impact on environment

Forms dense infestations, smothering native vegetation and preventing native seedling recruitment.

Control

Site Management

Follow up treated areas 3 times per year. Encourage natural regeneration of native plants or replant treated areas where possible after 2-3 treatments to establish dense ground cover and minimise reinvasion.

Recommended approaches

Physical control

Method: Dig out.

Plant parts requiring disposal: All parts.

Disposal options: Remove to greenwaste or landfill.

Biocontrol

Biocontrol is currently not available for this species.

Community agrichemical control recommendations

No qualifications: For small infestations on terrestrial sites: cut stump and paste freshly cut base of stems with metsulfuron gel. For small infestations on aquatic sites: cut stump and paste freshly cut base of stems with double strength glyphosate gel.

Basic Growsafe certified: For medium infestations on terrestrial sites: cut stump and spray freshly cut base with 1g metsulfuron-methyl per 1 L of water. For medium infestations on aquatic sites: cut stump and spray freshly cut base with 250ml glyphosate green per 1 L of water.

Certified Handler/Experienced agrichemical user: For large infestations on terrestrial sites: cut stump and spray freshly cut base with 1g metsulfuron per 1 L of water. For large infestations on aquatic sites: cut stump and spray freshly cut base with 250ml glyphosate green per 1 L of water.

Caution: When using any herbicide or pesticide please read the label thoroughly to ensure that all instructions and safety requirements are followed.

Close up of shrub basalm flowers.
Flowers are the same as the smaller impatiens flowers. Seeds form in husks that dry over the warmer months and as they dry pressure builds up so that when the seeds are ready they are released in a small explosion.
Photo credit: Jonathan Boow
A mature shrub balsam specimen.
Another popular garden plant that has been able to adapt to NZ conditions. Shrub balsam can grow in coastal areas, native forests, shaded areas, wastelands and areas that have been disturbed.