It would be well worth the try, some places list Anise Hyssop at z4. Even if those plants die, they should give you abundant seedlings next spring to the point of weedyness, and will flower the 1st year. I bet the seed plants will do OK, they are tough natives although short lived (2-3 years). I never ever lose 1st year plants here in z5 (outside Chicago). HereÂs a page from Trudi D on how to collect seed if you wish.

Here is a link that might be useful: Garden Web Trudi D

I grow it in zone 4. I have the native variety, not a cultivar. It reseeds quite well and is a magnet for finches and other birds, not to mention the bees and butterflies.

I've never grown it, but I am also a zone 4 and have had luck growing zone 5 plants when I place them in a sheltered location such as alongside an outbuilding where much of the wind is blocked. Good luck!

Anise Hyssop will grow for you, I'm sure. It sure grows well for me here in Wisconsin on Lake Michigan. I'm pulling up seedlings all summer long and I started with a small plant several years ago. It's like the energizer bunny, it just keeps going and going and going---