Noxious Weeds
The Province of Alberta has many noxious weeds noted on their website, but three weeds have been noted to be especially problematic in the Town of Bon Accord. These three weeds are described below. For a full list and description of provincially regulated weeds, please visit https://www.alberta.ca/provincially-regulated-weeds
A colony-forming, aggressive perennial, that spreads primarily by its creeping root system. Stems are grooved, upright, hollow and woody, branching near the top, and grow to 1.5 m tall. Leaves are lance-shaped, dark green, shiny on the surface and occur alternately, slightly clasping the stem. Lower leaves are largest and decrease in size upward along the stems. Leaf edges can vary from smooth with no spines to irregularly lobed with sharp spines. Flowers form at the ends of stems in clusters of one to several. The flower head is urn-shaped and the bracts are spineless. The color of the flowers may vary from plan to plant, being purple, pink or white. Seeds are borne in an achene to 4 mm long which is tufted.
Key Identifiers
- Deep creeping roots
- Irregularly-lobed leaves with spines on margins only
- Male and female flowers on separate plants
Rhizomatous perennial that can grow to 1 m. The usually unbranched stems are often reddish purple below, either hairy or smooth. Leaves are alternate, 3-7 cm long. Lower leaves are long-stalked and heart-shaped with coursely toothed margins. Upper leaves are sessile and lance-shaped with some hairs on the lower surface. Flowers are light purple to blue and borne in the axils of the supper leaves flower stalks. Inflorescence is frequently curved, giving an attractive 1-sided appearance. Flowers are composed of 5 united sepals and 5 united petals. Seedpods formed below the calyx and corolla, somewhat spherical containing many very fine seeds.
Key Identifiers
- Very persistent, widely spreading, fleshy, whitish underground rhizomes and thickened storage tubers
- Many heart-shaped, irregular toothed leaves
- Bell-shaped blue/purple flowers
Scentless chamomile is an annual to perennial plant that grows to 1 m tall from extensive, fibrous root systems. Stems are highly branched. Leaves are alternate, odorless when crushed, 2.2 to 7.5 cm long, and divided into numerous, narrow, thread-like, branched segments. Plants produce numerous flower heads. Flower heads are 2.5 to 4.5 cm in diameter. Disk florets are yellow. Ray florets are white and 9.5 to 19 mm long. Both disk and ray florets are capable of producing viable seeds. Seeds have three distinctive ridges.
Key Identifiers
- Large yellow-centered flower heads with white ray florets
- Tall, usually up to 75 cm with many branches
- Stems below the flower heads are smooth and hairless
- Whole plant is virtually without odor
- Seeds strongly 3 ribbed