Smallflower Touch-Me-Not

Smallflower touch-me-not (Impatiens parviflora)

Report

Barbara Tokarska-Guzik, University of Silesia, Bugwood.org

Management Strategy

Synonyms

Scientific:

Impatiens nevskii

Common:

Balsam
Small balsam
Small-flowered jewelweed
Small yellow balsam

ID Characteristics

General: This species is a frost intolerant annual succulent herb that grows 20 – 60 cm tall.

Flowers: Pale yellow flowers with red spots on the inside occur in the leaf axils. They are 15 – 20 mm long.

Stems: Erect to ascending, smooth, succulent and single-stemmed or branched from the lower nodes.

Leaves: Alternate along the stem, stalked, egg-shaped to elliptic, finely and sharply saw-toothed. They are generally 3 – 12 cm long.

Seeds: This species produces 10 – 20 mm-long capsules that contain many seeds and explode when touched.

Roots: Shallow and fibrous.

Similar Species

Native

Jewelweed (Impatiens capensis) can be found throughout the Sea to Sky. Unlike Smallflower Touch-Me-Not, its flowers are orange and spotted.

Orange Jewelweed (Pixaby)

Invasive

Himalayan Balsam (Impatiens glandulifera) is another invasive species that can be found throughout the Sea to Sky. Compared to Smallflower Touch-Me-Not, the plant is taller and has pink flowers.

Himalayan Balsam

Habitat and Origin

Smallflower touch-me-not is native to central Asia. Like other impatiens, it was likely brought to North America as a garden ornamental. The earliest known record of Smallflower touch-me-not in BC is in 1949.

Smallflower touch-me-not is very adaptable: it does well in partial to full shade and will grow in moist to damp areas, but it can also withstand drier conditions. It is generally found along river edges, wetlands, lake shores, forest edges or clearings.

How it Spreads

This species reproduces by seed. The plant produces seed capsules that explode when touched, effectively ejecting its seeds. One plant can produce a maximum of 10,000 seeds (although most plants produce between 1000 – 2000 seeds), which can remain viable in the soil for 3 years.

The exploding seed capsules can cause the seeds to travel up to 3.4 m away from the parent plant. Longer-distance dispersal is generally caused by water flow, or mowing after seed set. Seeds can also be transported on the bark of timber and the fur of mammals. Lastly, humans are also responsible for the plant’s spread, as Smallflower touch-me-not is still traded and planted for ornamental purposes.

Impacts

Ecological:

Displaces native vegetation on stream banks, ultimately reducing biodiversity.
Increases ditch and stream bank erosion.
Alternate host for crop pests such as cucumber mosaic virus.

Economic:

Infestations can choke drainage ditches, causing important infrastructure repair costs.

Stop the Spread

Smallflower touch-me-not is abundant in certain portions of the Sea to Sky region, but has not yet infested all potential habitats. The goal is to contain the spread of Smallflower touch-me-not to ISMA 2.

Learn to identify Smallflower touch-me-not: use the images presented on this profile page to learn how to identify Smallflower touch-me-not.

What to do if you spot it: You can report any Smallflower touch-me-not sighting by clicking here.

DO:

Regularly monitor properties for weed infestations.
Minimize soil disturbances and promptly revegetate disturbed areas to prevent the growth of smallflower touch-me-not.
Check wildflower mixes to ensure that they do not contain smallflower touch-me-not.
Ensure all flowering heads or buds are bagged or covered to prevent spread during transport to designated disposal sites.

DO NOT:

Unload, park or store equipment or vehicles in infested areas; remove plant material from any equipment, vehicles or clothing used in such areas and wash equipment and vehicles at designated cleaning sites before leaving infested areas.
Plant smallflower touch-me-not in a garden, no matter how well-contained its enclosure may seem.
Compost any flowering heads or buds. Instead, dispose of smallflower touch-me-not in the general/household waste stream at the landfill as the seeds may survive the composting process.
Move soil, gravel, or fill that has been contaminated with smallflower touch-me-not.

Control

Mechanical

Smallflower touch-me-not is relatively easy to control if it is pulled up by hand. As an annual plant, its root system is very limited, so it is easy to pull up. The seeds last in the soil for up to 3 years, so it is possible to control an infestation with a few manual removals. Note that pulling the roots from the soil is not recommended when the plants are growing adjacent to streams as disturbance to the moist soil will likely cause stream bank erosion and possible alteration to the stream course.

Chemical