First published 2013 23/11/2015 18:36 Shutterstock Invasive: High impact Invasive: Documenting Ireland’s Wildlife Ireland’s Documenting Himalayan balsam colony - balsam colony Himalayan

C. O’ Flynn Please report your sightings of this species at: this species of sightings your report Please http://invasives.biodiversityireland.ie Terrestrial. Riverbanks, roadsides and waste ground. and waste roadsides Riverbanks, Terrestrial. Established. 10ft). (approx 3 metres up to grows 3-5 in whorls of opposite and serrated, Green mid-rib. reddish also have may a deep which change to stems hollow Brownish/green head. owering the fl closer to colour red with wide . ower shaped fl Pink trumpet to easy making it very roots, shallow The plant has very pull the ground. out of a of which sets when touched, Ripe explode Seeds also explode. seeds to other amongst reaction plant. the parent from 7 metres up to can be spread

Himalayan Balsam Himalayan glandulifera Impatiens Dense stand of Himalayan balsam in a wet woodland - woodland balsam in a wet Himalayan of Dense stand Height: Status: Reproduction: when mature. pods explode features Identifying Widespread. in Ireland: Distribution name: Family Balsaminaceae. Leaves: Stem: : Roots: Seeds: Habitat: Species profi le profi Species The National Biodiversity Data Centre Data Biodiversity National The Invasive Species set 3.indd 11 Himalayan Balsam Invasive: High impact

Threats

Outcompetes native species by forming dense stands.

Can raise the risk of fl ooding as large stands can impede the fl ow of a waterbody.

Seeds are easily spread by both wind and water, making it easy to colonise areas further downstream.

During the winter the plant dies back, leaving river banks vulnerable to erosion.

Similar species

Spring: Seedlings present, can be told apart from native by stem structure and shape. Notice the red stems and seed pods of Himalayan Summer: Characteristic fl owers appear, making it easy to identify. balsam- Shutterstock Autumn and Winter: Early autumn plant may still be in fl ower, further into winter hay like remains of the plant are found.

Similar species When not in fl ower it may at a glance be mistaken with Himalayan knotweed (invasive).

Due to the formation of dense stands, it could also be mistaken with other invasive knotweed species, if seen at a distance.

It may also be mistaken with nodosa and two native species, which can also be found along riverbanks. Extreme care must be taken that these species are not exterminated alongside similar looking Impatiens glandulifera. Close up of flowering heads - O. Duffy

Shallow roots make the plant extremely easy to pull from the ground - C. O’ Flynn Scrophularia umbrosa also grows along riverbanks and can appear similar to Himalayan balsam - WikiCommons

View Ireland’s distribution of this species on http://maps.biodiversityireland.ie Biodiversity

National Biodiversity Data Centre fact sheet. Produced with funding from The Heritage Council Maps and the EPA STRIVE Programme 2007-2013 Text: Colette O' Flynn & Oisín Duffy (Version 1) November 2013.

Invasive Species set 3.indd 12 23/11/2015 18:36