I have one anise hyssop in my herb garden. It was planted from a 3 inch pot early last spring and it branched out and produced more than one bloom and bloomed several times during the summer. I cut the flowers back after it bloomed. I do have a long growing season here and it is planted on a south facing hillside.

Linda

But, you're referring to the Anise Hyssop (A. foeniculum) seed in the Johnny's Seed catalog (or a similar source), it is considered a "tender perennial." Johnny's says they are hardy in zones 6-9. They aren't hardy here. We would treat this one as an annual; and, we would start the seed in the greenhouse the first week in April (just like salvia farinacea).
It's now April!!Wow. What happened to March? Anyway, we would then plant good size plugs (deep 72s) out in the field mid-May. They produce many, many stems for cutting; and, we'd start harvesting mid July. If you're direct-seeding,
I would guess harvest may be set back a couple weeks.

FWIW -- The stems also require special post-harvest handling with our humidity here in the Midwest.

Trish

As a matter of fact, I did not grow it specifically as a cut flower the first year, and thought the dried seed heads looked nice, so I left them. Last spring I was overwhelmed by the amount of agastache seedlings everywhere. Last season I was much more careful to dead head whatever I didn't cut, and to manage the seeds, as opposed to letting them fall where they may.

:)
Dee