I'm in z6a and the blue Agastache foeniculum does well here, but it needs full sun to do well. I've tried to grow the orange, purple and red Agastache cultivars that have the southwestern A. cana genes in them, and they won't overwinter for me, even with excellent drainage. You might be able to pull them off in zone 7 if you give them good drainage.

And it took me years to crack the Heuchera growing code...otherwise they would slowly dwindle and disappear over 2-3 years. I like them, even started a butload from seed this year (doing very well), but I'd say dip your toe slowly to avoid wasting money.
Jay is correct, the SW Agastache are very very finicky about drainage and moisture during dormancy and early spring. They don't usually do well outside their native range (or a climate similar). And if you WERE to try them, don't buy any till spring, they need a full hot season for their best chance to live.

Thanks again for the insight, that's very helpful and it's appreciated.

The best Agastache I grow is A. 'Blue Blazes' bred and sold only by High Country Gardens. My oldest plant is probably 5 or 6 years old now. It's gorgeous. Looks more like A. foeniculum than like the other agastaches, but is handsomer and blooms longer.

Yes, and only spring planting.

Dbarron, please share the heuchera code! Is it regular dividing? Mulching in winter? Fertilizing? Removing flower stems??

I have both heuchera and agastache In zone 6b New York and don’t see them at all in the same category design wise. The heuchera are glossy leaved and have generally deep jewel tone colors, low sending up delicate flower stems. I think of them as lacquerware. The agastache are taller snd denser, generally matte and paler in foliage and flower. They’re sturdy paper plates, abundant and appreciated.

No, (at least for my climate), it's providing mostly shade, and protection from water (under roof overhang duplicating where they're found under bluffs in my area). I might water if they wilt, but otherwise, leave them alone. Note that three species of heuchera are native to my area.

Like Jay, I have not had good luck with the orange and red agastaches - they don't survive my winter, although admittedly I haven't tried one again in probably well over 10 years. Agastache foeniculum, on the other hand, is a wonderful, care-free, hardy plant here.

I find heucheras to be tricky. I haven't grown them in some time in my own garden because I thought they were finicky, but I do tend a few other gardens and they do okay there. Not great, not horrible. In one of the gardens literally one variety absolutely throve in one spot and twenty feet away the same variety dwindled, even though the only difference was the second one got ten more minutes of sun lol.

But you are a zone warmer, so bottom line, if I like something enough to give it a try, I will. With climate change and microclimates, you never know what might or might not work for you. Personally I would start by trying one of each and see how they do. Good luck if you do!

:)
Dee

I have no clue what it is about heuchera that makes them finicky -- the only variety that ever did well at my other house was "Citronelle", and it was a stunner in part-shade. I wasted countless dollars on other varieties that petered out after a year or three. Here I have a handful of "Grape Expectations" and they are thriving; their success has me open to buying other varieties should the need/desire arise.

Thank you all kindly. I think I'm going to wait until spring and get Agastache foeniculum and try my hand and the orange one. They'll also be in full sun locations.