Sla#s wrote:
Does hormone rooting compound weaken with age?
Should it be bought fresh every year?

This is an evergreen favourite! There's a school of thought which
says it's probably past its best before you even get it out of the
shop, because of the poor storage conditions. I'm sure it wouldn't
last a year. (And many or most of us here seem to reckon it's only of
use for the more difficult cuttings anyhow. Using too much is
certainly going to work against you.)

But PBI, the Baby Bio company, reckon an unopened pack of theirs has
a shelf-life of two years, and, if you're lucky, that an opened one
will last as long. I'm sceptical.

Mike.