Montana Field Guide

Chicken-sage is a mat-forming perennial herb or sub-shrub with multiple flowering shoots that are 5-20 cm high and many shorter, sterile shoots. The alternate leaves are up to 15 mm long and are narrowly fan-shaped and usually 3-lobed at their tip. They are aromatic and densely covered with appressed, gray hair. Several short-stalked, globose flower heads are borne at the stem tips. Each head has numerous disk flowers and 2-3 series of overlapping, membranous-margined involucral bracts that are 3-4 mm high. There are no ray flowers, and the achenes lack a pappus.

Flowering occurs in June and early July.

Chicken sage resembles a small, low-growing sagebrush plant (Artemisia spp.) but has fewer heads per stem. The flower heads are larger and tightly clustered, and the basal leaves are lobed nearly to the base. Recent research supports the placement of Sphaeromeria in Artemisia (Garcia et.al. 2011).

Chicken-sage generally grows on shallow limestone-derived soil of sagebrush steppe in the valley and foothill zones. Associated vegetation is quite variable, but all habitats are arid, alkaline and have low vegetation competition.

In the Grasshopper drainage of Beaverhead County, it occurs in two distinct habitats: 1) localized sandy clay pockets of sagebrush steppe dominated by Artemisia arbuscula/Agropyron spicatum, and 2) limestone outcrop ridgetops and slopes covered by dry bunchgrass communities of Agropyron spicatum and cushion plants, at the most sparsely-vegetated local extreme (Heidel and Vanderhorst 1996). In the Rocky Hills and near Bannack, chicken sage grows in openings of a limber pine (Pinus flexilis) and mountain mahogany (Cercocarpus ledifolius) community. Subdominant grasses include Elymus spicatus and Koeleria macrantha. Associated forbs include Erigeron compositus, Erigeron tweedyi, Haplopappus acaulis, Ivesia gordonii, Penstemon aridus and Penstemon eriantherus, all of which are characteristic of limestone outcrops.

In the Sage Creek drainage, this species has been found in heavy soil of eroding slopes at about 6300 feet elevation; common associates include Haplopappus acaulis and Erigeron tweedyi (Lesica and Vanderhorst 1995). It also occurs in this area on dry, rocky bunchgrass slopes not confined to limestone parent material; common associates include Ceratoides lanatus, Selaginella densa, Antennaria microphylla, Astragalus miser, Haplopappus acaulis, Eriogonum mancum, and Erigeron caespitosus. In the drainage of upper Big Sheep Creek, the habitat is an unusual alkaline bottomland community dominated by low sagebrush (Artemisia arbuscula) and greasewood (Sarcobatus vermiculatus).

Chicken sage is a long-lived perennial. Populations are generally sparse but often widespread. It occurs in many different common habitats but occupies only a small proportion of the apparently available habitat. Chicken sage is aromatic like closely related species of Artemisia and Tanacetum.

The species is an aromatic sub-shrub that grows low to the ground and is likely unpalatable or not affected much by livestock grazing (Vanderhorst and Lesica 1994). Where it grows on steep, rocky slopes, it is not very vulnerable to mechanical disturbance, such as trampling by cattle. However, bottomland habitats are more vulnerable. Grazing, mining and other activities may promote the spread of exotic species such as Bromus tectorum, Centaurea maculosa and Melilotus spp. The species is widespread in southern Beaverhead County, although never abundant. Some populations occur in historic mining districts and could be threatened by future mining activities. However, many of the known populations face no anthropogenic threats.

STATE THREAT SCORE REASON
Threat impact not assigned because threats are not known (MTNHP Threat Assessment 2021).