It is a member of the local serpentine soils flora, found at elevations of 1,600–2,800 metres (5,200–9,200 ft) in yellow pine forest habitats within the Shasta-Trinity National Forest.

Eriogonum siskiyouense is perennial herb forms mats up to 0.5 metres (1.6 ft) wide around a woody caudex.

It bears clusters of small rounded to oval leaves each under a centimeter long and coated in gray woolly fibers at least on the undersides.

The flowering stem arising from the caudex has a whorl of two to four leaflike bracts around the middle and is otherwise naked but for a coat of woolly hairs.

Atop the scape are the bright yellow flowers, which are usually arranged in a spherical cluster.