Diario de kurtsteinbach

Two species of willow that pose considerable difficulty in differentiating are Scouler's and Sitka willow. Both have similar growth habits, bark and leaf morphology. They also often share habitat. Scouler's tolerates dryer conditions than Sitka, which likes wetlands. But Sitka can be found at higher elevations, and Scouler's can be fond in wetlands. Whew!

Add to this the times of year both bloom. Sitka blooms from March to April. Scouler's blooms in February. Fair enough. But what about some years where things are early or late?

Here's what might help if you are looking at trees after the leaves mature. Sitka leaves have small red hairs on their under side. So do Scouler's. But! Scouler's looses most of the hairs as the leaf matures, except for along the veins.

I know, not the easiest way to distinguish these two species, but at least we have this one tool.

Source: http://web.pdx.edu/~maserj/ESR410/Salixsitchensis.html