(Typha angustifolia)

Three types of cattail are found in the Lakehead Watershed – one native and desirable, and two aggressive and invasive. Broad-leaved, or common cattail (Typha latifolia) is the “good guy”. Narrow-leaved cattail (Typha angustifolia) is an invasive species. The third cattail is created when the other two types of cattail crossbreed, creating the hybrid cattail (Typha x glauca). Both Narrow-leaved and Hybrid cattail can take over wetlands, spreading quickly to form monocultures and crowd out native species.

Invasive Cattail Fact Sheet

(Alliaria petiolata)

One of Ontario’s most aggressive invaders, Garlic Mustard is easily identified by a strong garlic odor emitted from young leaves when crushed.  During its first two years of establishment, it has two distinct life stages.  In its first year, dark green, kidney-shaped leaves with scalloped edges grow in low-lying basal rosettes.  In its second year of growth the plant sends up a long stem, 0.3 to 1.2 metres tall, with triangular, sharply toothed leaves alternating along the stem.  Second year plants produce small white flowers with four petals that turn into long seed pods (siliques) 3-6 centimetres long mid-summer.  The low-lying, kidney-shaped leaves from its first year of growth are still present.

(Impatiens glandulifera)

Initially introduced as a garden ornamental, Himalayan Balsam is a commonly found invasive species around Thunder Bay that shades out native understory vegetation.  Known for their “exploding” seed pods, Himalayan Balsam resembles other flowers in the genus Impatiens, commonly known as “touch-me-not’s”.  When the seed capsules mature and dry they will explode when touched, quickly spreading seeds and expanding existing populations.  It typically grows 1-3 metres tall, its stem is tinged with red and its leaves are a deep green, 5-20 centimetres long with a pointed tip and finely toothed edges.  The flowers are pink with a hooded shape and bottom lip.  Find it along riverbanks, along trails and in fields.

(Pastinaca sativa)

Growing to a height of 0.5 to 1.5 metres, Wild Parsnip has a light green and deeply grooved hollow stem.  Its leaves alternate along the main stem and are composed of 2-5 pairs of opposing leaflets, with one terminal diamond-shaped leaflet.  The leaflets have saw-toothed edges and long petioles (secondary stems connecting the leaves to the main stems).  Small, yellow, 5-petalled flowers grow in 15-25 rays/clusters per flower head.  Each flower head has the appearance of a flat umbrella.  After flowering, small 5-7 millimetres fruits replace each flower.  The fruit is a dry, oval shell containing two seeds, light green in colour with light pink at the top of each seed.  Fruit dispersal takes place between August and November and can stay viable in the soil for five years.

(Lythrum salicaria)

Rapidly spreading across North American wetlands, shorelines and roadside ditches, Purple Loosestrife has already made its way to Thunder Bay.  Often composed of 1-15 flowering stems, the plant mass grows to 60-120 centimetres tall.  Stems are stiff, square (with 4 to 6 sides) and green in colour, turning to reddish brown or purple as they age.  Leaves are lance-shaped with smooth edges and fine hairs.  Flowers are deep pink to purple and arranged in a dense terminal spike of clustered flowers.  Each flower is composed of 5 to 7 petals, each around 10 millimetres long.

(Iris pseudacorus)

Frequently planted in backyard ponds and gardens, Yellow Iris forms dense stands and displaces native plants such as Northern Blue Flag Iris (Iris versicolor).  Flowers have three drooping, yellow sepals (they look like petals) with purple-brown markings that surround three smaller upright petals.  Leaves are flat, 2-3 centimetres wide and up to 1 metre long.  Yellow Iris is the only iris in North America with entirely yellow flowers, though when not flowering can easily be mistaken for the native Blue Flag Iris (Iris versicolor).  The native iris is smaller, with leaves 10-80 centimetres long and purple-blue flowers.

(Petromyzon marinus)

Adults are eel-shaped and 30 to 76 centimetres with no scales.  Skin is grey to dark brown with a lighter underside, and seven obvious gill openings.  Sharp teeth radiate around a tongue at the centre of a sucker mouth.  In partnership with Fisheries and Oceans Canada, LRCA maintains the Neebing Weir – a sea lamprey control structure – in an effort to prevent the invasive species from moving into inland lakes in the region.