Trip 6: Okotoks and the Foothills County roads

The vegetation framing this shot is a leaning, multi-stemmed riparian shrub-tree growing right at the water's edge of the Bow River, photographed dormant in mid-November. Smooth grey bark, slender arching stems and small dark persistent cone-like fruits on last year's twigs point to river alder (Alnus incana ssp. tenuifolia), the usual bank shrub on this stretch of river. A leafless phone photo cannot settle this: willow (Salix sp.) and birch (Betula sp.) overlap heavily in winter silhouette, so treat this as genus-level at best. No plant in the frame is identifiable as an Alberta-listed noxious or prohibited noxious weed, though riparian edges and bridge approaches like this one routinely carry Canada thistle, common tansy and creeping bellflower — none of which can be confirmed here.

This is the riparian edge of the Bow River at a highway bridge crossing southeast of Okotoks / Foothills County (50.8304, -113.4199), on the prairie-to-foothills transition. River alder, willow and water birch form the woody fringe along cut banks and gravel bars here, holding the bank against spring runoff and ice scour; the riprap and engineered slope visible on the far bank show the corridor has been reshaped, which favours fast-colonizing bank shrubs. The shrub is growing where it stands rather than being washed up.

Come back in leaf (June–August) and shoot: a close-up of a single leaf showing margin teeth and vein pattern, a close-up of a twig showing whether buds are stalked (alder) or sessile, the bark at eye level with lenticels in focus, and one of the persistent cones at macro distance beside a coin or finger for scale. A shot of the base showing how many stems emerge from the root crown would also help separate a shrub clump from a damaged single tree.

The plant filling the right half of the frame is a multi-stemmed riparian shrub growing on the cobble bank of a large prairie river, almost certainly a willow (Salix sp.) — slender, flexible, upward-arching stems rising from a clumped base right at the high-water line, with only a scatter of narrow, dried leaves left on 15 November. Alberta has well over a dozen native willows (Salix exigua, S. bebbiana, S. lutea, S. amygdaloides and others) that all look like this once the leaves drop, so species is not defensible from a phone photo. Nothing in the frame is confidently a listed noxious species, but river gravel bars in this part of the Bow corridor routinely carry Alberta Weed Control Act plants — Canada thistle, common tansy, absinthe wormwood, and occasionally salt cedar (Tamarix) — so the dry forb stems and grass in the foreground should be rechecked in summer before the site is called clean.

The coordinates place this on the Bow River at the Highway 24 crossing near Carseland, Foothills/Wheatland country east of Okotoks — a wide, cobble-bedded prairie river cutting through grassland benches. Shrub willows occupy exactly this band: the scoured cobble and sand between summer low water and the spring flood line, where ice shove and current kill off anything less flexible. Behind them the bank rises into balsam poplar gallery woodland and then cured mixed-grass prairie, and the bridge approach fill adds a disturbed verge strip that typically collects weedy species.

Come back in June or July and photograph one stem close up: upper and lower leaf surface (showing margin teeth and whether the underside is whitish), a twig showing bud arrangement and whether the bud has a single cap-like scale (diagnostic for Salix), and any catkins. A shot of the base showing bark texture and the overall clump, plus a wide frame showing how far up the bank the thicket runs, would let this go from genus to species.