Himalayan balsam

Impatiens glandulifera

Invader Images

    • Can grow 3-10 ft tall, and stems are slightly purple.
      Can grow 3-10 ft tall, and stems are slightly purple.
    • Himalayan balsam infestation
      Himalayan balsam infestation
    • Flowers look like other "touch-me-not" flowers, but are pink-purple.
      Flowers look like other "touch-me-not" flowers, but are pink-purple.
    • Leaf arrangement is opposite to whorled. Leaves are long, toothed, with a tapered point.
      Leaf arrangement is opposite to whorled. Leaves are long, toothed, with a tapered point.

Identification

Appearance

Impatiens glandulifera is a succulent annual than can be 3-10 ft. (0.9-3 m) tall. The stems are purple tinged, hollow and hexagonally angled.

Foliage

The foliage is opposite or whorled. Leaves are lanceolate to lance-ovate with acuminate tips. Leaves are simple, serrate and 6 in. (15.2 cm) long.

Flowers

Flowering occurs from June to October. The pink, irregular, solitary flowers appear on axillary stalks.

Fruit

Fruits are five chambered capsules that, when mature, explode expelling seeds forcefully. Each plant produces about 800 seeds.

Biology

ECOLOGICAL THREAT

Impatiens glandulifera is a prolific seed producer. As is typical of the "touch-me-not" family, its seeds are locally dispersed by the ballistic action of its fruit capsules. The seeds can be dispersed further if they reach moving water, which is not uncommon given the plant's preference for moist areas.

ORIGIN

Impatiens glandulifera was brought to Europe from its native range in the Himalayas in 1835. It was first noted to have naturalized in Europe in 1855. It is presently found in many countries in continental Europe and throughout the UK. Robinson (1908) did not report the presence of Impatiens glandulifera in the 7th edition of Gray's Manual of Botany. In the eighth edition of Gray's Manual, Fernald (1950) reported that Impatiens glandulifera was "becoming occasionally escaped from cultivation" and was found in Nova Scotia, southern New Brunswick, Quebec, Ontario and northern New England.

HABITAT

Meadows, fields, forest, forest edge, disturbed areas

LIFE CYCLE

It is an annual herb which thrives in riparian zones and disturbed areas. Its high reproductive rate, early germintation, propensity for establishing thick stands, rich nectar production, hardiness, and habitat tolerance and plasticity have allowed it to spread rapidly, dominate landscapes, and compete with and displace native plant species.  Impatiens glandulifera is a summer-annual, therophyte with no vegetative reproduction. Seed production varies with plant density. From germination flowering takes about 13 weeks and continues for another 12 weeks. Seed capsules mature producing up to 10 seeds and burst, expelling the seeds 3-5 m. Individual plants may produce more than 2,500 seeds in a vegetative period with taller plants producing more seeds and pods. I. glandulifera competes on river banks through synchronous germination of a large seed bank providing sufficient biomass to suppress neighboring species. This synchronous reproductive strategy is thought to rely on habitats with seasonally predictable disturbances such as flooding

Management Options

This species is considered a watch list species. 

***Check out the downloadable treatment sheet above***

MECHANICAL CONTROL

An annual with a shallow root system, this plant pulls up easily. A seed bank is present with 2 year viability - follow up control is recommended. Populations may be mowed but need to be monitored in case mowed plants resprout later in the season. Remove and carefully dispose of flower and seed heads prior to mowing.

CHEMICAL CONTROL

It does respond to herbicide, with early season control recommended to prevent flowering, and late season application to control late-season non-flowering plants. Flowering plants sprayed with herbicide still produce viable seed.

 

**Be careful not to damage or kill nearby native plants when conducting management work. And when using herbicides, always follow the instructions on the label.**