Salix humilis – Upland Willow

Upland Willow, Carp Hills (O. Clarkin).

Upland Willow or Prairie Willow is unusual in that it can grow in dry, sandy, or rocky sites, hence its name. There are few confirmed observations of this willow in the Ottawa area (iNaturalist), with most of them occurring in the Constance Bay dunes and the rock barrens of the Carp Hills.

Upland Willow has some similarities to the more common Bebb’s Willow (S. bebbiana):  leaf shape (oblong, elliptic, obovate), leaf veinlets impressed from above and raised below, and a pubescent (hairy) and glaucous (blueish-white) leaf underside.  However, it can usually be distinguished from Bebb’s Willow by the following:

Woolly leaf underside. Carp Hills (O. Clarkin).
  • The leaves are frequently involute – they curl upward and roll inward.
  • The underside is very woolly, more so than Bebb’s.
  • The habitat is usually dry where Bebb’s Willow would not be found.
  • The shrub is small, with a mature height from 1 to 3 meters.

Upland Willow may also be confused with Sage Willow (S. candida), but its leaves are usually smaller, narrower, and revolute, and it grows in wet, calcareous habitats.

Here are selected photographs with location coordinates in iNaturalist:

https://www.inaturalist.org/observations/9445424 – wooly underside of leaf – Carp Hills
https://www.inaturalist.org/observations/9378944 – shrub form and leaves – Carp Hills
https://www.inaturalist.org/observations/8680591 – shrub form and leaves – Carp Hills
https://www.inaturalist.org/observations/4900236 – June growth, shrub and leaves – Constance Bay
https://www.inaturalist.org/observations/2870286 – leaf close-ups – Constance Bay
https://www.inaturalist.org/observations/8353332 – shows obovate leaf shape variability – Gatineau Park
https://www.inaturalist.org/observations/33121541 – small shrub in the Carp Hills