Aggressive Ornamentals

Himalayan Balsam (Impatiens glandulifera)

Himalayan Balsam is native to the Himalayan region of Asia. It has escaped garden cultivation to invade many areas, predominantly river edges, riparian areas and wetlands. It is thought to have been introduced to BC when foreign ships emptied ballast water into harbours. Plant seeds are very buoyant and they may have floated into local rivers where they found an ideal habitat to grow. It is currently found throughout the Lower Mainland and Fraser Valley of BC.

Biology

Himalayan Balsam is a annual herb with a thick, much branched, hollow stem, purple to reddish tinge, growing to 0.6 to 2 metres tall. Leaves are stalked, oblong to egg-shaped and have a serrated edge. It usually germinates in late winter to early spring and flowers from early summer to early fall. Flower are predominately pink, white or purple and shaped much like an English policeman's helmet.

Reproduction

Reproduction is only by seed. One plant is capable of producing up to 800 seeds, which can be viable for 18 months or more. Seeds are even known to germinate under water. When mature seedpods are disturbed or touched it splits, ejecting its seeds up to a distance of 20 feet. Plants growing near watercourses can propel seeds into the water current where they can be transported great distances.

Habitat

Himalayan Balsam has escaped ornamental planting to predominately colonize moist areas along river, stream and ditch banks. It prefers moist, rich garden type soil. It likes locations offering sun to light shade.

Concern

Himalayan Balsam ejects seeds into rivers and streams which spread far and fast to new locations. Once established, tall Himalayan balsam competes effectively against native plants. In many places it has been known to suffocate native vegetation. Riverside and ditchbank infestations are spread quickly by mowing operations.

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