I wonder the same thing Stu. This cultivar is typically not advised in high heat and humidity.

I bought one this winter to try out. I actually bought a number of firs on firma to try. Getting through summer will be test one. Then the second hurdle will be root hardiness for me. I know Abies firma is zone 6, but I'm hoping the roots will be fine.

On the ACS database, there is a beautiful 'Blaue Hexe' shown from Tom Cox in Georgia. There must be hope if it can grow well in Georgia. Anyone know what conditions this one is growing in? Looks like it might be under the shade of a tree.

I also bought one on firma to give a try, not expecting too much, just try to give best possible chance/conditions and hope for the best, especially in my zone 8 southeast heat and humidity. I planted it late fall along with a dozen other Firs on firma cultivars. We will see how they get through the summer and if they can avoid a slow yearly decline. I have them in full sun 10am to 2pm and partial to filtered shade the rest of the time.

I'm not sure about 'Blaue Hexe,' but other A. procera I've tried here (all on firma rootstock) have not done well. All of my in-ground efforts have failed, and only one in-pot plant (an A. procera 'Glauca') has survived multiple years. And it's a scraggly, rather pathetic thing. But I'm going to try again with a 'Rick's Foxtail' this spring. Finding the right site is so critically important with so many non-native plants...

What is the purpose of using firma understock?

Hi Scott!

I remember while back reading [a thread about using Firma for understock.[(https://www.houzz.com/discussions/its-all-in-the-abies-roots-dsvw-vd~1846329?n=16)

it might answer some of your questions. :o)

scott , also subscribe to Conifer Kingdom news letter , they recently explained

ron

I haven't read the CK newsletter, but my understanding is that the primary purpose for using firma rootstock is to prevent root rot in heavy soils. However, as noted above, it won't work for every species - some firs won't last in heat and humidity regardless of their roots. And even with firma, I'd be very cautious about putting any fir in 10 hours of direct sun in July (at least here in Atlanta).

I will second that thought?

For anyone that is interested, I ordered two Blaue Hexe on firma from conifer kingdom about a year and a half ago. I live in zone 7a, south shore of Long Island, NY. Lost one of them due to heat and humidity stress. The second one is alive, but lost a tiny bit of its needles, so It may make it in its new home.

Still a fickle conifer for the east coast of the US, IMO. They don't mind the heat as long as the humidity is relatively low, and the temperature cools down significantly at night. That is just not the climate we have here in this area. What firma does for you is help fight against root rot, but the foliage is still from Abies procera, and the foliage is what we care about when looking at this plant.