Montana Field Guide

Rhizomatous. Stems 50–100 cm, glabrous to pubescent, light brown. Leaf blades 2–6 cm long, glabrous, glandular-serrate above, entire near the base, green above, paler beneath. Inflorescence hemispheric, 15–50 mm across. Flowers: sepals ca. 1 mm long; petals rose, ca. 2 mm long. Follicles 2–3 mm long (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Pyramidal Spiraea is a natural hybrid between Spiraea douglasii var. menziesii and Spiraea betulifolia var. lucida, which are all present in Montana.

Rose Meadowsweet – Spiraea splendens, native:
* Inflorescence is flat-topped to hemispheric, broader than long.
* Flowers are rose.
* Leaves are hairy on the margins.

White Spirea – Spiraea betulifolia, native:
* Inflorescence is flat-topped to hemispheric, broader than long.
* Flowers are white.
* Leaves are glabrous.
* Montana’s variety is lucida.

Douglas Spirea – Spiraea douglasii, native:
* Inflorescence is cone-shaped, at least three times longer than broad.
* Flowers are pink to rose.
* Montana’s variety is menziesii.

Pyramidal Spiraea – Spiraea x pyramidata, native hybrid:
* Inflorescence is cone-shaped, about as long as broad or up to twice as long as broad.
* Flowers are pink-tinged.

Source: Lesica et al. (2012).

Stony soil of open forest, rock outcrops, moist meadows, avalanche slopes, often along streams, lakes; subalpine, rarely montane (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

POLLINATORS
The following animal species have been reported as pollinators of this plant species or its genus where their geographic ranges overlap: Bombus vagans, Bombus auricomus, Bombus fervidus, Bombus nevadensis, Bombus ternarius, Bombus griseocollis, and Bombus impatiens (Macior 1968, Heinrich 1976, Colla and Dumesh 2010, Colla et al. 2011, Koch et al. 2012).