The main sagebrush on our property is tall or big sagebrush (Artemisia tridentata). However, there is an area of silver sagebrush (Artemisia cana). As I read about the two different sagebrush species I became fascinated by the differences between these two shrubs.
As I noted before, the tall sagebrush on our property hosts sagebrush stem galls while the silver sagebrush had none. There is so much that is unknown about sagebrush galls that the only statement about galls I feel justified in making is that at this time on our property (Lookout CA) there are fruit fly galls on the tall sagebrush but not the silver sagebrush.
The Bolander subspecies of silver sagebrush found in our area is a lower growing shrub while tall sagebrush is medium-sized to tall. Silver sagebrush will resprout from its roots after the top is cut or disturbed while tall sagebrush does not. The leaves provide one of the most obvious field differences: tall sagebrush has evergreen, narrow, wedge-shaped leaves with three shallow lobes on the top while silver sagebrush leaves are deciduous, entire and narrowly linear.
The two species prefer different habitats. Tall sagebrush usually occurs in drier well drained soils while silver sagerush (Bolander subspecies) prefers poorly drained clay soil that is wet or seasonally waterlogged. The presence of tall sagebrush usually indicates good agricultural soils, a fact utilized by early settlers. Leonard and I have noticed on our ranch that where the soil is deeper the tall sagebrush produces taller mature plants while in shallower soil the mature tall sagebrush is shorter. Tall sagebrush is strongly aromatic compared to silver sagebrush’s faint aroma.
The inflorescence provides another clue to identification. The tall sagebrush flower cluster is wide, long, triangular in shape and has many erect side branches. Silver sagebrush inflorescences are narrow and resemble a spike without side branches. Unfortunately the two species were photographed at different times of the year.
It is interesting how two sagebrush shrubs can look so similar at a distance and upon closer examination are very different. OK! I am done with sagebrush posts – for now.