Wild Flower Wednesday: Alberta's Provincial Flower

Longhorn Beetle  Clytus ruricola  probably doing a fair job of pollinating an Alberta Wild Rose

What better way to re-start Wildflower Wednesday than with the official Provincial Flower of Alberta: Prickly Wild Rose Rosa acicularis (aka Arctic Flame)? Well, there are roads reputed to be paved with such good intentions. I've assumed our wild roses were acicularis, but a little bit of research shows that there are actually 4 species of wild rose reported from Alberta.

Flower colour varies within a species and in age of bloom, but this bumble bee is a good pollinator: Bombus ternarius

 The USDA lists Rosa acicularis, arkansana, blanda, and woodsii in Alberta. Unfortunately, the USDA maps show distributions only by state/province. If the species is there in said political entity, then the whole province gets coloured-in. Finer details like ‘does it grow on my land’ are obscure. Still, painful experience assures me we don’t have Smooth Wild Rose (R. blanda) – it has few thorns. Also, the above ground canes of insidious thorns persist, so it seems unlikely we have Prairie Rose (arkansana), which dies back each winter.

Looking more globular than pear-shaped,
these hips are probably Rosa woodsii

That leaves us with the Provincial Flower, Prickly Wild Rose, and the other, just as prickly, Wild Rose (Rosa woodsii). For most characters, these species overlap – and in fact they hybridize - so intermediate forms may be common where they overlap in distribution (aka where I live). The easiest way to tell these species apart is by the distribution of prickles and glandular hairs in relation to the stipules, but this is getting pretty technical and not possible to resolve from photographs. I will say that I did key out one plant to acicularis, but most of the pictures I have on hand seem more likely woodsii. I probably have a mix of both species.

Added bonus - prickly leaf galls caused by
minute gall wasp Diplolepis bicolor

Seems like I will need to wait until next summer to do a more thorough analysis of what wild roses our lands are supporting, including the one started from a cutting that is now occupying a good portion of the backend of the Home Bug Garden. Until then, take my word for it – both are excellent for pollinators and both host a diversity of other interesting insects. One great example, is a tiny wasp (Diplolepis bicolour) that causes Prickly Rose Gall on the leaves. And these galls, in turn, host other insects. You can barely discern one to the left in the picture below - another tiny wasp artfully inserting its eggs into the gall - probably so its larvae can eat the wasp that made the gall.

Tiny chalcidoid wasp putting its eggs into a Prickly Rose Gall

Colourful fungi like the rose rusts (Phragmidium spp.) also make use of our wild roses. As long as they leave our domestic roses alone, I don't think I mind the rusts eating the wild roses.

Aecial stage of rose rust on Wild Rose (probably R. woodsii)