These two sage species have the kind of extensive root systems that help them survive wildlife grazing, drought and winter. And both are "increasers" as they are native plants that increase in size and number to take the place of grasses removed by overgrazing.

Pasture sage (Artemisia frigida)

• Native perennial shrub with stems that live over the winter and branch from near the base.

Pasture sage is noted for its relatively deep and extensive root system, which enables survival on many types of sites. Well-developed taproots are produced where deep moisture penetration occurs. But where surface moisture is greater or where water penetration is prevented by runoff, no well-developed taproot is formed.

A fine network of fibrous roots off the horizontal stem is frequently concentrated near the soil surface. Rooting depths of 18 to 65 inches have been reported. Average maximum rooting depths within the same soil zones in Saskatchewan ranged from 16 inches on upper slopes to 50 inches on lower slopes.

Prairie sage (Artemisia ludoviciana)

• Native perennial forb: a broadleaf plant with an annual top and net-like veins in the leaves.

The extensive root system is generally a dense, coarse root mass located from 1 to 4 inches below the soil surface. This root system helps the plant spread fast and live long: colonies have been reported reaching diameters of 50 feet on lowland sites in Montana, with annual radial increases averaging approximately 1.2 inches. The larger colonies appeared to be approaching 200 years of age or more. On disturbed sites in Idaho, plants produced abundant rhizomes and fibrous roots during their first year.

Source:
"Alberta Range Plants and Their Classification", AAFRD
USDA Fire Effects Information Service database