We picked the elderberries in a local car park. I'd made cordial from the flowers of the same tree earlier this summer.
Consulted Violetta (this slim volume is great, out of print but available here).
Pre-mordanted silk and wool scraps into the dye bath. Note, or rather don't note the technique of the impatient dyer. You are supposed to drain out the plant material before you put in the fabric. Result? A good half hour at the other end of the process picking bits of twig and berry out of the material. . .
Paler than I expected. A pretty colour. Can't work out if this is a good thing. Anyway. Have frozen lots more for using at workshops etc.