The silverweed plant is used to heal cuts or sores. It is a coagulant like the yarrow plant. Ruth said,
It thickens the blood and it's a coagulant...therefore when you're bleeding pretty good, you drink the tea from this, or if you suspect internal bleeding and you don't have the yarrow...
The whole plant including the roots are washed thoroughly and made into a tea.
Source: Andre, Alestine, Nan t'aih nakwits'inahtsìh (The Land Gives Us Strength) (2006)