Weeds of Concern

The City has identified 12 noxious weeds as a threat to our community, and what you can do to help.

Photo of PURPLE LOOSESTRIFE

Purple Loosestrife

  • Stems are square, woody and grow up to 2 metres tall
  • Flowers are bright purple with wrinkled petals

Removal Tips

Photo of ORANGE HAWKWEED

Orange Hawkweed

  • Stems are leafless with bristly hairs and grow 15 to 60 cm tall
  • Flowers form at end of stems in clusters
  • Orange-red flowers composed of square-edged, notched petals

Removal Tips

Photo of HIMALAYAN BALSAM

Himalayan Balsam

  • Stems are smooth and grow up to 3 metres tall
  • Flowers are long in shades of pink

Removal Tips

Photo of OXEYE DAISY

Oxeye Daisy

  • Stems are smooth and grow up to 1.5 metres tall
  • Flowers are white with a yellow centre

Removal Tips

Photo of GARLIC MUSTARD

Garlic Mustard

  • Dark green kidney-shaped leaves; stays green throughout winter
  • Flowers are in clusters at top of the stem and have four white petals

Removal Tips

Photo of DAMES ROCKET

Dame's Rocket

  • Stems branch at the tip and grow .5 to 1 metre tall
  • Flowers are shades of lavender-pink through purple and white

Removal Tips

Photo of LEAFY SPURGE

Leafy Spurge

  • Stems are arranged in clumps and grow up to one metre tall
  • Flowers are small and yellowish-green

Removal Tips

Photo of COMMON BURDOCK

Common Burdock

  • Purple flowers and a red-tinged stem
  • Leaves are large, hairy and heart-shaped

Removal Tips

Photo of FLOWERING RUSH

Flowering Rush

  • Stems are erect and triangular near the base
  • Leaves are green and sword-shaped, they originate from the base of the plant

Removal Tips

Photo of SCENTLESS CHAMOMILE

Scentless Chamomile

  • Flowers are composed of a yellow central disk surrounded by white petals
  • Leaves are alternate and very finely divided into short segments (carrot-like) and odourless when crushed

Removal Tips

Photo of COMMON TANSY

Common Tansy

  • Leaves alternate on the stem and are deeply divided into numerous narrow, individual leaflets with toothed edges
  • Flowers are yellow, numerous, and button-like, occurring in dense, flat-topped clusters at the tops of the stems

Removal Tips

Photo of FIELD SCABIOUS

Field Scabious

  • Are hairy and the degree of the lobes is highly variable
  • Are a composite of small, violet-blue florets clustered into a head resembling a single flower up to 4 cm wide, and occur singly at the ends of stems

Removal Tips

For a list of invasive species fact sheets and more information on invasive plants in Alberta, visit the Alberta Invasive Species Council.


Related Pages

Last edited: March 22, 2021