Oh boy, good stuff, Susan!
I like to harvest just as the flower buds begin to show but the leaves are fine by themselves, up until that point. I don't know your environment but I don't want to inhibit the plant too much in growing large and developing. So, I use last year's dry herb until a later harvest. Generally, I have lots of seedling volunteers to work with. Not this year however . . .
I do, however, think you are correct that any pinching should result in a bushier plant. You may even get away with that pinching, at the base of the plant.
Reseeding has been the way I get new plants each year. The first year I had anise hyssop, it was in a flower bed between roses. Oh my, did those plants self-sow! There were hundreds
the following spring. That was about 8 or 10 years ago and the anise hyssop has been relegated to the veggie garden since then. Usually, they don't show up in huge numbers out there because the garden is tilled in the spring. I do get a dozen plants or more and move them around where they can grow.
This year, there are only 4, I think. For the 1st time in a long time, the "Tractor Guy" did not till my large veggie garden this year. That was me out there behind the Briggs & Stratton. I will probably have to rethink my growing techniques (or, lack of them) if this is going to be a result.
To my tastes, mixed about 1 : 1 with lemon verbena is the very
I hope you enjoy your plants.
Make everything as simple as possible but not simpler. ~ Albert Einstein